PALEOZOIC GROUP. 297 



Fucoids? resemble a Palceophycus; other raised markings are very probably 

 Stromatocerium; a much weathered impression has somewhat the appearance 

 of a Lamelli branch of early type; and one form is like Leperditia (not L. 

 anna, Jones> but more like L. Canadensis, Jones, of the Chazy.) It is prob- 

 able that special effort next season will enable us to collect more characteristic 

 specimens from the fossiliferous beds which are now known to occur in this 

 subdivision. 



(2) The Bluff Subdivision. — The blue magnesian limestones are com- 

 monly coincident in distribution with the buff dolomites, and sometimes they 

 form mesas or plateaus, but in many places they are still covered by the later 

 rocks. They occur usually in only a few beds, each from 5 to 20 feet in 

 thickness, perhaps 60 to 80 feet in all, as a maximum, but often much less. 

 There can be no doubt concerning the stratigraphic relation of this set of 

 beds to the strata above and below; but as no fossils have yet been discovered 

 in any of them, there is now no alternative except the adoption of a lithologic 

 classification, which is here made to correspond as closely with the facts as 

 present knowledge will permit. 



The rocks of this upper subdivision are dark magnesian limestones, as 

 seen in the bluffs, and they are usually preceded by brown beds of rather 

 dense crystalline granular texture. Upon fresh surfaces of fracture the 

 Bluff Beds are gray or bluish and rather compact, but they weather black, 

 and are frequently roughly pitted upon exposed surfaces. No fossils have 

 been discovered in them to the writer's knowledge. 



B. THE WTO DIVISION (MIDDLE CANADIAN?). 



The name Wyo is adapted from the well known cattle brand (Y 0) used 

 in the Blue Mountain region along the course of the James, River in adjoin- 

 ing parts of Mason and Kimble counties. The Wyo Division is not clearly 

 proved to hold the stratigraphic position here assigned it, although I have 

 always found the beds .lying directly beneath the next higher Hoover Division 

 when both occur in the same section, and there is no support to any other 

 designation, at least in my notes and those of my assistants; but in the dis- 

 trict where the best exposures occur, faults and other complications make it 

 wise to draw conclusions with great caution. I prefer not to commit my- 

 self to many details until more study has been given to the sections. How- 

 ever, in the San Saba Canyon, west of the Block House crossing, and upon 

 the James River near the boundary between Mason and Kimble counties, 

 the relations of this division to the subjacent rocks are apparently what 

 has been given here. The beds of this division are particularly well ex- 



