v 



states that the Memo 

 Times at the office of th 



3. Report of a Reeonnaisanee fro>n Carroll, Mo* 

 on the Upper Missouri to the 'YeJ!nir*t„„ f X<, /;»..,<// P<iri:. -W 

 return, ,»<<Je in the sum hmr <>f 1h7o; hv Wm. Li'dt.mw. Captain 

 of Em.rin.vrs. Brevet Lieut. Colonel C.'s. Arm v. Chief Engineer 

 Department of Dakota. Being Appendix NN of the Annual 

 Report of the Chief of Engineers for 1876. 142 pp. 8vo. 1876. — 

 The report of Colonel Ludlow gives excellent descriptions of the 

 <>t' Montana and tin- region beyond traversed 

 by his expedition, with notes also on routes, canons, the geysers 

 of the Yellowstone Park, ami many other subjects of interest. 



The volume also contains a Zoological Repor by Gi .not !>nu> 

 Grinnell, which is an annotated Catalogue of Mammals and 

 C .!.._' ■..': [{ |. -rt by Messrs. Edward S. Dana and 

 G. B. Grinnell. The siibj.-eis treated -.fin the ia~t-.m .th-ned 

 report are the alluvial deposits of the Upper Missouri ; the Creta- 

 ceous at Carroll and beyond; the Judith Mountains, where were 

 Wd« of Civta.-eoiK age, and the trachytic "Com- Unite," a c«>ui«-:d 

 hill, .b.ut 3,400 feet in elevation above the level of the Mi-->uri 

 River, the average height of the Judith Mountains; the virinity 

 of the Moccasin Mountains, whose appearance ''indicated that, 

 like the Judith Mountains, they are largely tra. liyt'm ; v the 



„ of Camp Lewis, where ■_„„ _ 

 shale, and probably Cretaceous; the west end of the Judith 

 Mountains, in which limestone bluffs containing Carboniferous 

 fossils were visited; the region beyond to Camp Baker, passing 

 over Carboniferous limestone in Musselshell < anon, dipping 50° 

 to 60° to the south of west, which, through an overturn, was 

 overlaid by Lower Siluriai , and finding the 



central portion of the Litth Ih li Mom tains to .-.insist of trachyte; 

 Camp Baker and beyond toward Fort Ellis, where occurred, 

 besides the prevailing Miocene beds (containing remains of 

 On>o<h >n , Rhinoceros, etc.), a limestone of Primordial age, afford- 

 ing an Obolella, and new species of Trilobites of the genera 

 Arionellus and Crepicephalvs, along with red shales and quartzyte 

 of the same age ; tin liridger Mountains, having Cretaceous beds 

 on the east, next Jurassic (red bands, with Jurassic fossils), and 

 then Carboniferous limestone at the summit, with older rocks on 

 the west, having in places a reversed dip ; the geysers of the 



The occurrence of a Miocene Lake Basin in the vicinity of 

 Camp Baker is the subject of an article by the authors in vol. xi 

 ot this Journal (p. 126). The Cretaceous formation underlaid the 

 -1. The most prevailing 

 member was No. 4. of M.-ek and [lavden, or the Fort Pierre 

 Clays. But besides this, No. 5, or the Fox Hills Group, was 

 observed at several points, and No. 6, or the Fort Union Group, 



