B92 HONEYMAN' OK K',\A »COTIAN GEOLOGY. 



A. May hill sandstone of Salter^ directly with, the Medina sand- 

 stone, United States. As it is distinct from B. and B'. Clinton and 

 underlies it, it is reasonably regarded as the approximate equivalent 

 of the Medina sandstone, United States. In addition it is also a 

 sandstone. Sometimes I am disposed to subdivide and to make the 

 metamorphosed part in conjunction with the trap of Arisaig Pier, 

 and other parts of the shore — Oneida conglomerate. United States. 



I have referred to another division of the Arisaig Series into 

 Upper and Lower, the Lower Helderberg equivalent being the 

 Upper and the Clinton the Lower Arisaig. There are two applica- 

 tions of the word Arisaig. There is the Arisaig Township and the 

 locality Arisaig. In the former sense it is much too restrictive as 

 it ignores a great part of the Arisaig Series — besides a typical series 

 of crystalline rocks which I have elsewhere designated as "Lower 

 ' Arisaig " and carboniferous rocks. In the latter sense it includes 

 t<yo much, as the " Lower Arisaig " of the Division alone lies in 

 Arisaig, while the " Upper Arisaig " is in Moidart. On these 

 grounds I consider this division as untenable. 



From the considerations already stated I have long regarded 

 the Silurian fauna of Nova Scotia as Anglo-American. When 

 Mr. Salter examined my Arisaig collection at the London Exhibi- 

 tion of 1863, he marked particularly the English fossil Grammysia 

 Cingulata. Upon the authority of Professor Dana, — this is a 

 foreign form which has not been found elsewhere in America. In 

 England this fossil occurs in the Ludlow tilestone. In Nova Scotia 

 it occurs in the Upper Clinton of Arisaig. So that the Nova 

 Scotian Grammysia Cingulata is older than the others, and may 

 therefore at present be regarded as the ancestral Grammysia 

 Cingulata. 



In England and elsewhere Sir R. J. Murchison's division of 

 the Silurian system into Upper and Lower, has been generally 

 accepted. In America eminent Palseontologists, e. g. Hall and 

 Billings, have divided the system into Lower, Middle and Upper. 

 This is the division adopted by the New York and Canadian 

 Surveys. Professor Ramsay in his Geology of North Wales, 

 proposes a modification of Sir R. Murchison's division. Between 

 the Upper and Lower Silurian he distino-uishes an Intermediate 



