Geological Snirvei/ of the Yorkshire Coast. 423 



is no enemy which it fears openly to attack, and " none is so 

 fierce that dare stir him up." But all vitality, all muscular 

 energy, depends on the act and effects of respiration ; and 

 how are these habits of the crocodile to be reconciled with 

 this law ? On land, when breathing the atmosphere at full, 

 he is sluggish and fearful ; it is only when immersed in water, 

 and where respiration is liable to be impeded, that he acquires 

 strength, activity, and courage. There is here an exception 

 to the law, but it is only in appearance; and it is curious to 

 remark how simply nature in this case enlarges the respiratory 

 organ and function, and gives to the aquatic creature its cor- 

 responding power, without deviating in any thing from the 

 one model of organisation. By means of two canals, which 

 take their origin in the cloacum, and which open into the 

 cavity of the peritoneum, water is conveyed within the abdo- 

 men to act upon the blood in its vessels ; and through the 

 abdominal vessels, thus called upon to aid the lungs in -oxy- 

 genating the blood, the additional vigour to the muscular 

 system is imparted. The crocodile has an abdominal sternum 

 independently of its pectoral sternum : each sternum and its 

 muscles regulate the effects of their proper and respective 

 respiration. When the animal is on land, it is the thorax 

 and its sternum which are only in action : when in the water, 

 the abdomen and its sternal apparatus are likewise called into 

 play. Isidore Geoflfroy Saint- Hilaire and Joseph Martin were 

 the discoverers of the canals which open into the peritoneum ; 

 a discovery of great interest, as previously to it the habits of 

 the crocodile were inexplicable* 



N. 



Art.it. a Geological Survey of the Yorkshire Coast, describing 

 the Strata and Fossils occurring between the Humber and the Tees, 

 from the German Ocean to the Plain of York. By the Rev. 

 George Young, A.M., assisted by John Bird, Artist, Members of 

 several Local Philosophical Societies. Second Edition, 1828. 



The district which this volume is proposed to illustrate is inferior to few 

 portions of our island in geological interest, as it regards what are commonly 

 termed the secondary formations, or those which contain organic remains, 

 from the chalk to the lias inclusive. ** Nowhere," the authors observe, 

 " have the fossil relics of animals and vegetables been found in greater 

 variety and abundance. Almost every stratum teems with substances for-, 

 merly endowed with life and motion ; and the fossil conchology of the dis- 

 trict might, of itself, occupy a large volume. Hence, not only the mere 

 geologist, but the student in natural history, may here find an employment 

 adapted to his taste, in comparing the recent productions of nature with 

 those which have been embedded in the bowels of the earth, and which are 

 fitly regarded as the medals of nature's history." The authors, who had 

 previously occupied themselves in preparing the geological portion of The 



