147 



this class, and there can be little doubt that their dis- 

 tribution is practically world-wide. 



Accidental stragglers to our coast arc not infrequent, and 

 the only marine reptile given in the table may be taken as 

 an instance, viz.: the Hawk's Bill Turtle (Chelone imbri- 

 cata), a resident of tropical waters, found dead off Redcar 

 in 1849. Other rare stragglers are the Opah or King Fish 

 {Lampris /una), of brilliant colours, a native of the Atlantic 

 and Pacific Oceans; the Tunny (Tkunnus thynnus), a warm- 

 blooded fish ; the Pilchard (Cluftea pilchardtts) : and the 

 Basking Shark (Cetorhinus maximus), the latter being the 

 so-called '"grampus." which created such a sensation on 

 Redcar Sands two years ago. 



Concerning the history of the marine fauna of Cleveland 

 very little can be said here. We may endeavour to find out. 

 however, the period when the animals first appeared on our 

 coast. Of course, the obvious answer to this problem is, after 

 the North Sea was formed, but when this took place the 

 geologist can only assign a relative date. That the North Sea 

 existed in pre-glacial days is certain, and that it contained a 

 fauna even richer than the present one is also certain. For in 

 those well-known formations of Pliocene times — the Crags of 

 Norfolk and Suffolk — are to be found shells precisely similar 

 to those in the present sea. together with species now extinct 

 or living elsewhere, and indicating a somewhat warmer climate. 

 In many of the glacial beds of the Cleveland district, frag- 

 mentary shells of Cyfirina islaitdica, Tellina balthica, and 

 Dentalium enlalis are of frequent occurrence, and they also 

 prove the existence of the North Sea in pie-glacial times 

 from the bed of which they were carried by the great northern 

 ice-sheet. For during the Ice Age it seems fairly well estab- 

 lished that the German Ocean was filled with thick glacier-ice. 

 and that consequently the pre-glacial marine fauna was either 

 driven away southw aids or became extinct locally : but with the 

 retreat of the ice and the gradual amelioration of the climate. 

 the various species would return to repopulate their old haunts. 

 We have to picture to ourselves this great movement of 

 marine animals, some creeping from rock to rock along the 

 coast, others being carried helplessly by the currents and tides. 

 and yet others actively swimming through the water. At 

 first the northern forms now confined to the Arctic Province 



