342 THE CANADIAN NATURALIST. [Sept. 



pact in size, admirably arranged, its well filled pages beautifully 

 illustrated, it brings up every department of geology to the latest 

 point in regard to facts, while the discussions in regard to 

 theoretical views are very strict, pithy and well-weighed. While 

 the formations of Europe are, as is usual in British text-bool^'s, 

 taken as types, those of other parts of the world are well worked 

 in ; and a fair share of attention is given to the discoveries which 

 have recently been made on this continent. 



Sir Charles notices fully the recent remarkable discoveries of 

 fossils in the Lower Cambrian of Britain, which extend a rich 

 fauna back into the Longmynd Group, at one time supposed to be 

 nearly barren of fossils. He proposes, in connection with this 

 to establish firmly the once debateable Cambrian system, and to 

 extend it as far upward as the Tremadoc. He thus arranges 

 these rocks : — 



Upper Cambrian : 

 Tremadoc Slates (Primordial of Barrande in part.) 

 Lingula Flags (Primordial of Barrande.) 



Lower Cambrian : 



Menevian Beds (Primordial of Barrande.) 



7- T r^ {a. Hailech Sfrits. 



Longmi/nd ixroup < . ° 



(. b. Llanberis slates. 



He regards the Potsdam Sandstone as equivalent to the Upper 

 Cambrian, and places the Huronian as the possible equivalent of 

 the Lower Cambrian, He barely notices our richly fossiliferous 

 Lower Potsdam or Acadian group, and does not include it in his 

 table, though it would have enabled him to find an equivalent for 

 his Menevian beds. He still regards Ilistioderma as a worm- 

 burrow, not being, apparently, aware of Mr. Billings' more pro- 

 bable explanation of it as a cast of a sponge. 



It would, however, be useless to follow in detail a work of this 

 kind, which every student and amateur in geology should have 

 in his hands as a book of reference, and which as nearly as is 

 possible in that science whose goal to-day is its starting point 

 to-morrow, brings up the subject to a level with the present 

 state of knowledge, and compresses all its more important facts 

 into the shortest possible space, while exhibiting them with the 

 utmost clearness. 



Geological Discoveries in Brazil. — The following letter 

 to one of the Editors from Prof. Hartt, a Nova Scotian by birth 



