10 research outputs found
Culturing soles on ragworms: growth and feeding behaviour
No full textEnde, S.S.W. (2015). Culturing soles on ragworms: Growth and feeding behaviour. PhD thesis, Wageningen University, The Netherlands. Despite the high market demand and intensive research efforts since the 1960s commercial culture of common sole (Solea solea L.) has been unsuccessful. Problems related to availability and price of suitable raw materials (invertebrates) and the low tolerance to crowding have hampered the development of intensive sole culture. Alternative extensive pond cultures systems are currently explored where common sole can graze on natural food. The general aim of this study was to get insight into which factors limit growth of common sole foraging on ragworms in ponds. The results did not show any nutritional effects that may hamper the growth of common sole. At non-limiting conditions, i.e. when fed chopped ragworms and when housed in sediment free tanks, common sole showed higher food intake, higher growth rates and higher nutrient utilization efficiencies than when fed mussels or a formulated diet. The results however suggest that growth in a pond with ragworms was limited by reduced foraging capabilities of common sole. To explore this hypothesis, the effect of prey size, predator size and prey density were tested. Overall, intake of buried ragworms was reduced by more than half in contrast to intake of unburied ragworms. Intake of buried ragworms was reduced regardless of ragworm size or common sole size. Increasing ragworm density only resulted in satiation intake values in smaller common sole. Our results additionally indicate that the presence of common sole hampers ragworm performance in a pond. Ragworms reduced their feeding activities when receiving water from tanks which contained common sole and ragworms, i.e. when common sole could graze on ragworms. Results from this PhD study suggest that the growth of common sole in ponds is not limited by nutritional but by their foraging abilities. However, the results of this study are too incomplete to fully predict growth performance of common sole in a pond. Factors such as temperature, oxygen supply or feeding activity need to be investigated to make comprehensive growth predictions. </p
The influence of prey size, sediment thickness and fish size on consumption in common sole (Solea solea L.)
No full textThis study determined prey consumption in common sole as a function of prey size (0-0.5, 1-1.5, 2-2.5 and 4-5 g), sediment thickness (20 cm and 2 cm) and fish size (50 g, 125 g or 300 g). Prey consumption (in numbers of prey eaten per fish per day) was reduced with increasing prey size and sediment thickness, and was increased with increasing fish size (p < .001 for all factors). All 3 factors showed significant two way interactions (p < .001) when expressed in numbers of prey eaten. Prey consumption decreased with prey size when prey could not escape by burying (2 cm of sediment thickness) irrespective of fish size. We suggest that increasing effort to ingest and handle larger prey played a role. Prey consumption increased with fish size when prey could not bury (2 cm of sediment thickness). However, when prey was able to bury (at 20 cm sediment thickness) prey consumption was similar irrespective of fish size (p < .001 for interaction fish size × sediment). This interaction suggests that with increasing fish size there is an increasing mismatch between foraging adaptation and prey burial depth. This may explain the dominance of crustaceans in the diet of adult common sole in nature, despite the high abundance of polychaetes
Feed intake, growth and nutrient retention of common sole (Solea solea L.) fed natural prey and an artificial feed
No full textThis study compares growth, intake and retention efficiencies of nutrients and energy between common sole (Solea solea L.) fed ragworm (Nereis virens, Sars), blue mussel (Mytilus edulis L.) and an artificial (commercial) feed. Food types were fed to common sole (mean initial body weight: 44.9 ± 2.3 g) in excess three times a day over a 54-day-period. The growth rate in common sole fed the natural prey (8.5 g kg-0.8 d-1) was significantly higher compared to the growth rate in fish fed the artificial feed (5.1 g kg-0.8 d-1). Nutrient and energy intake was significantly lower in common sole fed the artificial feed than in fish fed natural prey. The only exception was fat intake which was higher in common sole fed the artificial feed in contrast to fish fed the natural prey. Nutrient and energy retention efficiencies were significantly lower in common sole fed the artificial feed than in fish fed the natural prey. In conclusion, the low growth in common sole fed the artificial feed was related to lower nutrient and energy intake as well as lower nutrient and energy retention efficiencies. It is suggested that reduced intake of the artificial feed might be related to the high dietary fat content of the artificial feed
Is growth retardation present in Nile tilapia Oreochromis niloticus cultured in low water exchange recirculating aquaculture systems?
No full textIt has been suggested that fish cultured in recirculating aquaculture systems (RAS) grow less as compared with fish cultured in flow-through systems due to the accumulation of substances. In the Netherlands, the commercial culture of Nile tilapia Oreochromis niloticus in 300 and 600 MT's systems is done exclusively in RAS operated at water exchange ratesas low as 30 L/kg feed/day due to nitrate control by single-sludge denitrification reactors. The use of such nearly closed RAS raises the question whether growth retardation (GR) is present in Nile tilapia. This study is the first to investigate the existence of growth retardation in Nile tilapia by comparing the growth, feeding behaviour and stress response of Nile tilapia cultured in RAS with different levels of substances accumulated. Three RAS, operated at 30 L/kg feed/day (HIGH accumulation), 70 L/kg feed/day (MIDDLE accumulation) and 1500 L/kg feed/day (LOW accumulation) were used. Each RAS contained 24 glass aquaria with individually housed fish. To determine whether GR is size-dependent, per RAS 3 fish size categories were tested in the 57 day experimental period: large (288.7 +/- 34.2g; N=8), medium (162.4 +/- 23.4g: N=8) and small (81.4 +/- 21.0g; N=8). Experimental fish were fed ad libitum, twice per day. Feeding behaviour was determined once per week and was measured as the time taken by each fish to eat the first pellet (latency, LAT) and the total time spent feeding (total feeding time, TFT). Temperature, pH. conductivity, alkalinity, dissolved oxygen, dissolved CO2, nitrogen compounds (TAN, NO2-N and NO3-N), chemical oxygen demand and orthophosphate-P were measured over time. At day 57 fish were weighed, blood sampled and returned to their tanks for an extra experimental period of 15 days, and subjected at day 72 to an acute stress followed by blood sampling. Blood was analysed for glucose and cortisol. Results showed that the water quality parameters measured in the 3 RAS (with the exception of alkalinity) were still within the optimum range for growth of Nile tilapia. Large individuals showed a tendency to grow more in the LOW treatment (2.66 +/- 1.35 g/kg(0.8)/day) as compared with the MIDDLE treatment (0.93 +/- 1.63 g/kg(0.8)/day). On the contrary, small individuals grew significantly less in the LOW treatment (3.60 +/- 1.74 g/kg(0.8)/day) as compared with the HIGH (7.22 +/- 1.58 g/kg(0.8)/day) and MIDDLE (6.82 +/- 4.54 g/kg(0.8)/day) treatments. Small fish were more motivated to eat (lower latency) in the MIDDLE (4.63 +/- 5.24 min) as compared with the LOW treatment (8.94 +/- 6.41 min). In the HIGH accumulation treatment higher glucose levels were observed in the small fish, before and after acute stress, as compared with the LOW accumulation treatment. In conclusion, this study showed that the extent to which the accumulation of substances in RAS affects growth depends on fish size: large individuals show a trend towards growth retardation in the highest accumulation RAS while small individuals, on the contrary, seem to grow better in such systems
The accumulation of substances in Recirculating Aquaculture Systems (RAS) affects embryonic and larval development in common carp Cyprinus carpio
No full textThe accumulation of substances in Recirculating Aquaculture Systems (RAS) may impair the growth and welfare of fish. To test the severity of contaminants accumulated in RAS, early-life stages of fish were used. Ultrafiltered water from two Recirculating Aquaculture Systems (RAS), one RAS with a high accumulation of substances (water exchange rate 30 L/kg feed/day) and one RAS with a low accumulation of substances (water exchange rate 1500 L/kg feed/day), was used to incubate eggs and rear larvae of common carp Cyprinus carpio. A broad range of read-out parameters was used to determine the effect of accumulation level on the development of the early-life stages; from hatching dynamics to larvae length and dry weight. The water quality (temperature, pH, dissolved O2, conductivity, total bicarbonate, ortho-phosphate-P, TAN, NO2-–N, NO3-–N and minerals) was compared between the 2 treatments. Carp eggs developing in the high-accumulation water had higher mortality percentages (both for eggs and larvae), reduced hatching percentages, delayed hatching dynamics and reduced larvae length and body weight. However, these larvae exhibited fewer deformities than larvae incubated in the low-accumulation water. Furthermore, an accelerated development both of the embryo (appearance of heart beat, pectoral fin bud and tail movement) and yolk-sac larvae (depletion of the yolk sac) was observed in the high-accumulation water. The high-accumulation water had significantly lower pH and higher conductivity, NO2-–N, NO3-–N and ortho-phosphate-P. Most of the minerals (As, Cu, Mn, Ni, Zn, K, Mg, Na, P and S) including heavy metals, were present at a higher concentration in the high-accumulation water. The influence of these parameters on the embryonic and larval development of fish is discussed. It is suggested that in the high-accumulation water, the concentration of ortho-phosphate-P, nitrate and of the heavy metals arsenic and copper is likely to have impaired the embryonic and larval development and therefore deserves further research as potential growth inhibiting factors in RA
Comparing feed intake, utilization of protein and energy for growth and body composition in S. solea fed natural and commercial diets
No full textThe present work was carried out to study the effect of polychaete Nereis virens on feed intake, utilization of protein and energy for growth and body composition in sole (S. solea). It is hypothesized that intake, efficiencies of protein utilization and growth rates obtained for sole fed ragworm are comparable to those previously reported for S. solea. The mussel M. edulis was used as a reference diet to allow comparisons of present results with those obtained previously, which until today serve as reference for optimum growth in sole. Intake, efficiencies of utilization for protein and energy for growth and growth rates obtained for sole fed ragworm are expected to be higher compared to commercial feed. A commercial feed, commonly used for turbot but also in sole culture served as a second reference diet to discuss differences between natural and commercial feeds
Comparing feed intake, utilization of protein and energy for growth and body composition in S. solea fed natural and commercial diets
No full textThe present work was carried out to study the effect of polychaete Nereis virens on feed intake, utilization of protein and energy for growth and body composition in sole (S. solea). It is hypothesized that intake, efficiencies of protein utilization and growth rates obtained for sole fed ragworm are comparable to those previously reported for S. solea. The mussel M. edulis was used as a reference diet to allow comparisons of present results with those obtained previously, which until today serve as reference for optimum growth in sole. Intake, efficiencies of utilization for protein and energy for growth and growth rates obtained for sole fed ragworm are expected to be higher compared to commercial feed. A commercial feed, commonly used for turbot but also in sole culture served as a second reference diet to discuss differences between natural and commercial feeds
(An) experimental study on the surface roughness of the silver amalgam
No full text치의학과/석사[한글]
수복재료로서 Silver amalgam은 치과임상에서 가장 널리 사용되어 있다. Silver amalgam의 실패의 주원인은 파절, 변색과 부식, 수축과 팽창으로 인한 체적의 변화등으로 사료된다. 변색과 부식은 충전물의 표면 거칠기와 밀접한 관계가 있으며, 충전물의 연마를 잘 해줌으로서 변색과 부식의 예방은 물론 변연 적합도, 연조직 적합도, 청정의 용이등의 잇점을 갖게 된다.
이 논문은 Silver amalgam에 있어서의 연마방법에 따른 표면 거칠기의 효과를 알아보고자 재래식 TypeⅡ classⅠ amalgam을 사용하여 임상에서 많이 사용되고 있는 연마기구인 burnisher(DF29), mount stone(No.69), finishing bur(S.S.W. No.200), puemice와 zinc oxide powder에의한 연마후 Silver amalgam 표면을 surface roughness tester(model SE3AP롤 표면 거칠기를 측정하여 다음과 같은 경론을 얻었다.
1) Amalgam carver에 의한 표면 거칠기의 산술평균과 표준오차는 21.4μ±0.80, burnisher에서 5.4μ±0.37, mounted stone에서 9.3μ±0.58, finishing bur 에서 8.1μ±0.33, purmice와 zinc oxide powder에서 4.1μ±0.17로 나타났다.
2) pumice, zinc oxide pwder에 의한 표면거칠기가 carver, burnisher, mounted stone, finishing bur에 의한 표면거칠기보다 낮은 표면거칠기를 나타냈다.
3) mounteed stone 과 finishing bur로 연마한 표면거칠기는 유의의 차이가 없는 것으로 나타났다.
[영문]
To observe the effect of the polishing instruments on the silver amalgam restorations, the author has studied the surface roughness by means of the surface roughness tester (Model SE-3A). The polishing instruments used this study were the carver, the burnisher, the mounted stone, the finishing bur, and the purmice and zinc oxide powder.
The results obtained were as follows.
1. According to the polishing instruments, the arithmetic averages and standard errors of the surface roughness were the amalgam carver (21.4 micron ± 0.80), the burnisher (5.4 micron ± 0.37), the mounted stone (9.3 micron ± 0.58), the finishing bur (8.1 micron ± 0.33), the purmice and the zinc oxide powder (4.1 micron ± 0.17).
2. The surface roughness of the silver amalgam polished by the purmice and the zinc oxide powder was smoother than those of the silver amalgam polished by the carver, the burnisher, the mounted stone, and the finishing bur.
3. The surface roughness of the silver amalgam between the mounted stone and the finishing bur was not significantly different statistically.restrictio
The geology of the Highland Border from Tayside to Noranside
No full text1. The Highland Border Series: The rocks previously mapped as Margie Grits have been examined microscopically and are shown to resemble very closely those from other localities. In the R. Prosen there has been found a new group of fine grits, black shales, and chert,which are devoid of fossils but probably belong to the older Black Shale- Jasper Series.2. The Lower Old Red Sandstone: A petrological examination of the lava - -form rocks has shown them to belong to various sub- -divisions of the andesite and basalt families. The well- known "Lintrathen porphyry" is found to be a dacite and also a lava flow with a wide - spread occur- -ranee at one stratigraphical horizon. An investigation of the conglomerates has shown their reliability as stratigraphical indices, and a definite rhythmic variation in their composition has been demonstrated, upon which an interpretation of the conditions of their accumulation can be based. The tuffs and sandstones show a closely similar varia- -tion in composition.3. The Upper Old Red Sandstone: What may be a remnant of Upper Old Red Sandstone sediments has been found among the Margie Grits near Auchnacree.4. The Serpentine Belt: The rocks of the belt contain the remains of three types of ultrabasic igneous rock, HARZEURGITE, SERPENTINE-PEGMATITE, and 1)UNITE, and probably represent one plutonic intrusion; together with a smaller quantit of highly decomposed tuffs resembling schalsteins.5. Intrusions: Most of the intrusive igneous rocks are N.E. - -S.W. dykes of tholeiitic character, identical with the Salen type tholeiite from Mull. One sill near Bridge of Cally is probably associated with these rocks, re- -presenting a slightly-different phase of the vulcanic- - ity which may be of Carboniferous age. The dyke at Auchnacree is a pyroxene -basalt and may be connected with the igneous activity of Old Red Sandstone times.6. Sequence: A stratigraphic,al sequence of the Lower Old Red Sandstone rocks has been worked out on the field evidence evidence, and it has been found that the order and grouping is similar to that derived from the Kincar- dineshire rocks by R. Campbell. The nomenclature of that author is therefore employed.7. Tectonics: The investigation has revealed the existence' of a major Highland thrust with a minor one to the north, both of them being steeply inclined upthrusts from the north -west. Estimates of their magnitude are given. Beyond is a normal fault with its downthrow to the south -east. The rocks of the serpentine belt are bounded both to the south -east and to the north- west by planes of dislocation, evidence of contact metamorphism by the serpentine on the country rock being absent. The serpentine- schalstein complex is therefore thought to be older than the Lower Old Red Sandstone. There is a second group of dislocations - dip faults - cutting the Highland Boundary area in a direction N.N.E. - S.S.W. The Old Red Sandstone rocks lie in synclines elongated approximately parallel to the major thrust and fault lines, and in the north-westerly area overlie/
163 . overlie immediately a denuded halradian schist floor. In the middle and more easterly areas anticlinal folds occur in close proximity to the main Highland Boundary Thrust.8. The glaciation of the region has left extensive relics: New striae and roches moutonnées are recorded and various kames are noted. A series of marginal drainage channels has been mapped along the fringes of the Grampians, parallel to the main valley of Strathmore, and the possibility of their inter- communication in some cases discussed. Associated with these are certain lakes, but there are many others,at intervals along the course of the present river systems,of probably later date, when the melting snows followed the shortest route to Strathmore and cut deep gorges through the conglomerate ridges
An Orographic Sketch of Korea
No full textIn recapitulating what has been stated in the foregoing pages, I must first of all say that the geological-structural lines upon which the present paper has been woven, may not be entirely intelligible to the reader without some prefatory geological description accompanied by a geologic map. Some may even cast doubt upon my statements which, of course, must await verification by future observers. In regard to the geology of Korea, I hope I shall be able within a few months to give general outlines with an account of the geological history of the peninsula. Korea is, as I have said, the Italy of Eastern Asia jutting out southward from the main body of Manchuria, just as Italy does from the other end of Eurasia. It is limited on the north by the equatorial chain of Chyang-paik-san which is looked upon by the Koreans as an offshoot of the great Kuen-lun, after being interrupted in its eastward course by the depression of Liau-tung at I-wu-lii-shan. On the southern foot of the Chyang-paik-san range lies the basin of the Am-nok and Tu-man Gang which are separated from each other at Hyoi-san-nyong (700 m.) by a lava-flow from Paik-tu-san, the highest point (8,900 feet) of the Chyang-paik and the cradle of the Korean nation. The Alps and the plain of the river Po are the counterparts of these in the Italian peninsula. They lie nearly in the same latitude, enjoy a favourable climate, and are inhabited by peoples of very ancient culture. The peninsula is divisible on good grounds into two sections-North and South Korea-by a trench, in the geological sense, from the head of Gen-san harbour to Kang-hoa Bay, at one corner of which is located Che-mul-pho, the emporium and entrance to the capital Seoul. This trench or rift-valley is lava-drowned (Pl. I, Fig. 3) and ins the only extensive volcanic field in South Korea, except the large basaltic island of Chyoi-jyu (Quelpart) off the southern coast of Chyol-la Do. This rift-valley or Graben of Chyuk-ka-ryong (510 m.) affords the easiest passage obliquely across the peninsula from the Sea of Japan to the Yellow Sea, and marks the boundary of various geographic elements: a) Historically, North Korea is the land of Old Chyo-syon. The dynasties founded by Tan-gun, Keui-cha, and Ui-man under the name of Chyo-syon, and Ko-ku-ryo or Ku-ryo founded by Chyu-mong, all had their domains mainly in this portion of the peninsula. At a somewhat later time in South Korea sprung up the First Three Hans - Ma-han, Sin-han and Pyon-han, followed by the Second Three Hans of which Sil-la and Paik-chyoi occupied the south, and Ku-ryo only North Korea. From the historical point of view, South Korea is the land of the Hans. b) Climatically, the North is cold while the South is mild; the latter produces the rice, which is the main staple of the country. c) Topographically, the Han-land (South Korea) is hilly, though lofty mountains crown the high coast along the Sea of Japan, slanting gradually westward and disappearing under the shallow, turbid waters of the Yellow Sea. In North Korea we have the two topographic types of the Kai-ma plateau in the north (Figs. 3 and 4.) and the Paleo-Chyo-syon on the south (Fig. 5.), the latter being hilly land of the type of South Korea though on the average considerably lower. Consequently, the land gradually rises towards the east and most of the large rivers, such as the Am-nok, Chhyong-chhyon, Tai-dong, Yoi-syong, Im-jin, Han-gang, Keum-gang and Yong-san-gang empty into the Yellow Sea. d) The physique and temper of the people in both halves differ in no small measures. The peninsula of Korea presents most interesting problems in the arrangement of its mountains and in its underground structure. Professors. F. v. RICHTHOFEN and C. GOTTSCHE have made an attempt at their solution. On my return home from Korea this year, I had the great pleasure of reading SUESS\u27Antlitz der Erde which was soon followed by RICHTHOFEN\u27S Geomorphologischen Studien aus Ostasien, I, II, and III. The former author scarcely touches our peninsula, while the latter lets his Tungusic curve pass through the brinks of the East Kan-ma Land as far as to Ho-do (Hoa-do) near Hamheung, and makes the Korean curce start anew from here and go around the outer side of South Korea as far as to the mouth of the Yang-tze-Kiang. The two curves are said to enclose the land that corresponds to the inner Staffelland of the Great Khingan (Hsin-gan) and Taipanshan in China. The peninsula seems to have interested our two masters almost as deeply as it has the political leaders of our times. Let me try to reiterate what has been said in the present paper in regard to the geomorphology of the peninsula. i. Archaean formation composed, as elsewhere, of gneiss-granite, gneiss and mica-schists, is thrown into board, undulating folds on the front side of the peninsula, in the western portion of the Han-land and Paleo-Chyo-syon, becoming steeper as we go south. The axis of folding stretches from S.S.W. to N.N.E., or S.W. to N.E. Two prominent crests of this type are the No-ryong and Chhya-ryong ranges which extend obliquely across Chyol-la Do and Chhyong-chhyon Do. Besides, many small swellings of the crust-surface can be seen in the Paleo-Chyo-syon Land, though deeply hidden under the mask of Paleozonic formation. Nearly half of the area of the peninsula is occupied by holds of this class. These specialized folds should be classed, according to my view, with the Sinian System of South China, as was originally intimated by PUMPELLY. It is a well-known fact that F.v. RICHTHOFEN prolongs his ideal line of the Sinian System to the frame-work of South Japan, a view endorsed by DR. E. NAUMANN, and the late HARADA. L.v. Loczy is, on the other hand, disposed to think that its is the Tching-ling-shan that is prolonged to South Japan through the Hwai Mountains and the mouth of the Yang-tze-Kiang where the Sinian System clings to it (Anschmiegung). But no one knows what became of them after they disappeared in the Tung-hai. The broad belt of the Sinian System which obliquely crosses the Korean peninsula, if extended beyond the Tung-hai, will join with the mountains of South China, to which the same Sinian System was originally given by PUMPELLY. Baron v. RICHTHOFEN\u27S ideal line runs from South Japan to Fuchou and then goes along the coast of Fokien and Kwang-tung, as is well seen on H. FISCHER\u27S map of East Asia. As may be seen on any tolerably good map of South China, a greater portion of the Sinian System, of which Ta-yu-ling forms the axis, enters the Tung-hai between Fuchou and Shang-hai, and its further prolongation will correspond well both in its direction and its breadth to those which I venture to call the Sinian folds of Korea. It should be specially remarked that, if the Sinian System in Korea be prolonged to the north-east, a greater part of the folds will again unite directly with the tectonic lines of the Sichota-alin, as they are given in Ivanow\u27s work. (Pages 13-17.) ii. The Sinian represents an old system of crustal folds in the peninsula; and contemporaneously with it or a little later, there was generated another system in the Liau-tung direction in the Kai-ma Land, which was posthumously faulted in serial order towards the south, producing the parallel ridges of Myo-hyang-san, Tyok-yu-ryong and Kal-eung-nyong. These trend from W.S.W. to E.N.E. and form apparently the direct continuation of South Manchuria. The well-known Chyang-paik-san stretches, however, cast and west, obliquely meeting the preceding in the basin of the Tu-man Gang. The upper am-nok Gang drains the acute angled area between the two systems which are cut down crosswise by the Syo-Chyang-paik-san at the north-east coast of Ham-gyong Do. (Page 34.) iii. By the Korean System I mean that complex of uplifted edges and sometimes folds which run more or less in north-south direction along the long axis of the peninsula. It is so characteristic to the physiognomy of the land that even native geographers long before us recognized its great importance in the surface-features of the peninsula. It is also so peculiar to Korea that I know of no other mountains bearing the same trend as these in South-east Asia. I presume, however, that something like the Korean direction may perhaps be looked for beyond the Chyang-paik-0san range in Kirin and also at the terminal portion of the long ridge of the Great Khingan. Also a part of Kyu-shu (Japan) may be within its reach. Within the complex of the Korean System, there seem to exist two natural subgroups which are named respectively the Thai-Paik-san and the Syo-Paik-san. a. The first constitutes the backbone of the peninsula extending from the south-east of Kyong-syang Do toward the N.N.W., along the coast through Thai-Paik-san, O-dai-san and Keum-gang-san. After a short interruption it seems to stretch to Nang-nim in the Kai-ma Land which is separated by it into east and west halves, while at the same time it forms the boundary of Phyong-an and Ham-gyong. A sudden turn of the upper Am-nok, -the Angle of Mao-erh-shan, -is probably due to its prolongation, while the axial trend of Ko-chyoi Island indicates how the mountains curve a little to S.W. on entering the south Korean Archipelago. Five components of the Thai-Paik-san are the cliffs of tilted blocks sweeping along the coast of the Sea of Japan, from which the right wing was successively thrown down to the sea-bottom, as if it originated in disjunctive faults as an after-effect of the piling and pressing up of Hondo (Japan) toward the pacific ocean. (Pages 17-22.) b. The second or Syo-Paik-san subgroup is also composed of fault-scarps which trend south of south-west. This sub-group builds the water-parting and boundary-wall between Kyong-syang on the one side and Chyol-la and Chhyung-chhyong on the other. Instead of maintaining the nearly parallel course of the members of the Thai-Paik-san, the four component-ridges of the Syo-Paik-san diverge from near the pass of Chhyu-phung-nyong in feather form in South Chyol-la Do. In its north-eastern course the Syo-Paik-san is cut off by the Thai-Paik-san, exactly as the fold-crest of No-ryong, already described, which, however, differs slightly in direction and greatly in its structure from the Syo-Paik-san members. (Pages 22-26.) iv. No less remarkable than the preceding is the direction of the Han-san range which chiefly confines itself to the southern border of South Korea. It trends from W.S.W. to E.N.E.; and corresponds well with the north side of South Japan, but as regards its western prolongation it is no easy matter to conjecture what will be its probable continuation. I simply suggest the idea that we might look for its linear extension in the basin-ranges that govern the course of the Lower Yang-tze Kiang. These low ranges seem to belong neither to the Kuen-lun, nor to the Sinian. (Page 31.) The Han-san Range resulted from a later geologic even than that which produced the Korean System. The former is composed of a number of tilted edges of faults which threw down block after block to the Southern Sea. The sea-coast is dotted with an innumerable number of islets and rocks, and describes complicated in-and-out curves. These peculiar features which characterize the coast, are nothing more than the outcome of the joint-work of the orogenic movements that gave form to the Korean and Han-san ranges. The inlets are the remains of tectonic valleys, while the headlands represent the ridges. Especially remarkable is the narrow canal of the free port, Ma-san-pho which presents the outline of a compound cross with a single axis, due to the Korean and Han-san ridges which intersect each other on both sides of the entrance. (pages 26-31.) This is a special form (PI. III, Fig. 2) which truly deserves an independent position in the list of many coast-types. I name this the Nam-hai type as this special kind of coast-line is seen all along the shores of the Nam-hai or South Sea of South Korea. v. A great number of small ridges or fault-scarps traverse like a gridiron the whole of Paleo-Chyo-syon. The region is somewhat similar in its geological structure to the western half of Shan-tung. Well-established rules can be scarcely discovered in the arrangement of ridges. The whole tract is broken up into a number of long orographic blocks, each being of old sedimentaries, mainly of grey tabular limestone. Each block is tiled along the long side with steep walls, while it slants gradually towards the opposite direction. Some of the equatorial ridges may be brought into connection with the tectonic line of Shan-tung, e.g., Myor-ak-san of Hoang-hai Do, while others of the same group are difficult to correlate with any known system. Meridional ridges, though coinciding in direction with some of the Korean System, do not harmonize with each other in position, nor in magnitude of disturbance; the general plan of the west coast, however, seems to have been greatly influenced by them. (Pages 46-50.) In short, the intercrossing fault-scarps of Paleo-Chyo-syon inserted between the Sinian and Liau-tung systems seem to be the result of a passive movement and after-effect of the still greater tectonic disturbances which gave to the crust-block of the Korean peninsula its present form
