14 HONEYMAN — ON NOVA SCOTIAN GEOLOGY. 



Brook is their place of meeting, and I thought to make this also the 

 point of geological separation, but fortunately I found a nodule with 

 a distinct Graptolithus Clintonensis on the shaley side of the line ; 

 so if this is to be regarded as a distinctive Fossil, Doctor's Brook 

 shale is also a lower part of Lovrer Arisaig, and is also Clinton. 

 The Petraia slates at Doctor's Brook are lithologically and pal^eon- 

 tologically distinct from the shales. They were considered by 

 Salter to be the equivalents of the May Hill sandstone of Great 

 Britain. There is every probability that they are the equivalents of 

 the Medina sandstone of the United States. Underlying these is 

 a metamorphic band — until lately I have regarded this as a portion 

 of what I have designated the Medina sandstone equivalent. I 

 now regard it as the equivalent of the Oneida conglomerate, U. S. 

 This includes the red Jaspideous rock of the Arisaig Pier and the 

 Frenchman's Barn (rock) a considerable mass of rocks at Doctor's 

 Brook, and similar rocks to the west of McISTeil's Brook on the shore. 

 Connected with these in the last mentioned locality, I discovered a 

 soft variegated rock which strikingly contrasts with the hard un- 

 yielding character of its associate. It is easily polished, and may 

 be useful for ornamental purposes. At first I regarded it as 

 Steatite, and then Rensellaerite. It is now considered to be a 

 silicate of alumina — agalmatolite. I subsequently found it also in 

 the same connection at Arisaig Pier, and it was afterwards found 

 near Frenchman's Barn. In this locality there are veins of it, 

 yellowish and translucent. Here it has since been quarried to 

 some extent by a company formed for the purpose. It is reported 

 to be serviceable for pottery. These rocks are considered to have 

 been altered by the great dyke of greenstone, greenstone porphyry 

 and amygdaloid, which is in contact v/ith it throughout the entire 

 length of the band. 



It may tend to confirm my view of its equivalency if I quote 

 the views of Dr. Dav/son in reference to the character of the rocks 

 in question: "It is a very instructive study to compare the soft 

 conglomerates and their interstratified trap at McAra's Brook, with 

 the continuation of the same body eastward of A.risaig Pier 

 where they appear forced into hard quartzose rocks, in some of 

 which the original texture is entirely obliterated." {^Acadian 

 Geology, 1st ed. page 268.) 



