President* s Address. 19 



terus. To me this discovery is particularly interesting, as I 

 had been led to infer from the structure of the Carboniferous 

 Eurypterus that it was a land animal. Additional proof in 

 support of this conclusion was obtained by Sir W. Dawson 

 in the old tree-stumps of the Joggins Coalfield, where he 

 found masses of the test and the comb-like organs of a 

 Eurypterus, besides the remains of reptilians, gally-worms, 

 and a snail {Pupa vetusta) — all land animals and air-breathers. 

 The value of palseontological evidence in determining the 

 geological position of strata is admirably illustrated in the 

 case of the Elgin sandstones. In that region a series of 

 yellow sandstones containing a remarkable reptilian fauna, 

 found elsewhere in Triassic beds, overlie Upper Old Eed 

 Sandstone rocks with remains of Holop)Ujc]iius. The physical 

 relations of these two groups of strata are obscured by a great 

 development of superficial deposits; but quite recently a 

 section has been exposed in a quarry near New Spynie, in 

 which the reptiliferous sandstones rest on the Upper Old Eed 

 strata, without any marked unconformability, save a thin 

 band of conglomerate. With reference to the age of the red 

 and yellow sandstones yielding Holoptychius, there has been 

 no difference of opinion. They form part of a group of Upper 

 Old Eed Sandstone strata extending along the south shore of 

 the Moray Firth. The overlying yellow sandstones contain- 

 ing reptilian remains have been generally regarded by geolo- 

 gists as belonging to the Triassic period ever since the 

 publication of Huxley's monograph on the fossils derived 

 from these beds. Notwithstanding the palseontological evi- 

 dence, a few geologists still cling to the belief that the 

 reptiliferous sandstones may eventually prove to be a higher 

 portion of the Upper Old Eed Sandstone. It seems to me, 

 however, that there is an overwhelming amount of e\ddence 

 supplied by the organic remains, in support of the Triassic 

 age of these sandstones. The mere fact of finding reptilian 

 remains or footprints is not enough to decide the question ; 

 but when we remember that these remains belong to true 

 Crocodilians {StagonoUpis) and to Lacertilians {Telerpeton), it 

 is sufficient to show that there is a great hiatus between the 

 two sets of rocks. The evidence is still further strengthened 



