130 THE HABITAT OF THE EURYPTERIDA 



From the point of view of the determination of the habitat, we 

 come now to the most significant occurrence of eurypterids thus far 

 known in the British Isles. To be sure the "seraphims" of the Old 

 Red Sandstone discovered by the stone-cutter of Cromarty and 

 proclaimed by Agassiz to be "the remains of a huge lobster," are 

 deservedly famous. Their size, abundance, association with the mon- 

 ster cephalaspid fishes, and above all the mystery attending their 

 place in nature have shed upon the eurypterids of the Old Red Sand- 

 stone a picturesque and historical glow which makes the later dis- 

 coveries of faunas merely so many cold triumphs of science. But 

 the light which the Devonic merostomes throw upon the solution of 

 the problem of the habitat cannot compare with that which emanates 

 from the fauna of the Wenlock. And the reason is this: A large 

 number of geologists have already come to the conclusion that the 

 Old Red Sandstone was a series of torrential and flood plain deposits, 

 in which case they can hardly fail to believe that the organisms found 

 in the deposits were river-dwellers. Furthermore, it will not be a 

 very difficult undertaking to convert the unbelievers in the river 

 origin of the Old Red to staunch advocates of it. In fact, we may 

 say that the case is so clear not only as to the lithogenesis of the 

 deposits of the Old Red Sandstone, but also as to the medium in 

 which the organisms of that time must have lived, that a few years' 

 from now there will probably not be any thoughtful geologist who 

 will not agree that the Devonic rivers supplied the sediments and 

 were also the home of the Old Red fishes and merostomes. But in 

 the case of the Wenlock it seems the rankest heresy to say that any 

 of the organisms whose remains are found therein could be other than 

 dwellers in the sea. The majority of palaeontologists would describe 

 the Wenlock as exposed in the inliers north of the tableland in some 

 such manner, "The Wenlock consists of a series of conglomerates, 

 mudstones and grits with intercalated shale bands which are usually 

 highly fossiliferous. While the coral fauna so characteristic of the 

 Wenlock of England is lacking, there abounds, nevertheless, a repre- 

 sentative marine assemblage which includes graptolites, brachiopods, 

 pelecypods, gastropods, cephalopods, Crustacea, and eurypterids. The 

 merostome fauna is one of the largest known from a single horizon, 

 comprising sixteen species, distributed in five genera, while the 

 remains are so abundant that certain layers are almost like coal beds, 

 they are so charged with carbon." Who, indeed, would have the 

 temerity to claim that such a fauna of eurypterids with such asso- 



