W. El. Herries — On the BagsJiot Beds. ITl 



diorite, norite, and angite-norite are alike in containing the same 

 bases in nearly the same proportions. The soda-granite differs in 

 chemical constituents only through its mica, which indicates the 

 presence of potash ; but the other rocks also are often micaceous 

 and contain in addition more or less orthoclase. Silica, alumina, 

 iron protoxide, magnesia, lime, soda, potash, are all the essential 

 ingredients obtained in analyses of these various rocks (excluding 

 the magnetite, apatite, pyrrhotite, and pyrite) ; and it is not 

 mysterious, therefore, that such rocks should be among the results 

 of metamorphism. 



The geologist will nowhere on the continent find a more instructive 

 spot for a day's walk than in the western portion of the Cortland 

 region. Starting from Cruger's Station (37 miles from New York 

 City), a walk of half a mile brings him to the western brick-yard shed ; 

 going north from here by a wood road carries him along section 3, 

 and in less than a mile in a northerly direction (passing brick-yards 

 at the end of it) he will reach Montrose Point and the chrysolitic 

 rocks ; following these around by the shore for about a mile he will 

 then pass a brick-yard on the Point, and beyond it find the norites 

 and chrysolite rocks together ; a mile and a half more (passing on 

 the route the large Verplanck ice-hoase) will take him to Broadway, 

 in the village of Verplanck, near the foot of which street, on the 

 shore, occur the limestone and its associated augitic and hornblendic 

 rocks. Thus, in a distance of seven miles, he will see a wonderful 

 diversity of rocks and facts. Possibly he may be convinced, at the 

 end of the walk, that igneous eruption explains everything. But let 

 him go over this ground a second time more carefully, then trace the 

 rocks of Verplanck Point north-eastwai'd, and afterward extend his 

 walks in other directions over the Cortland region, and he may see 

 enough to satisfy himself finally that, although there has been fusion 

 and some eruption, it was not eruption from the earth's deeper 

 recesses, like that which brought up trap (dolerite) through a series 

 of great fissures for a thousand miles along the Eastern Atlantic 

 border, from the Carolinas to Nova Scotia, all of it rock of one kind 

 essentially, but eruption from less depths, not greater than the lower 

 limits of a series of formations that were subjected together to fold- 

 ings, fi-actures, and metamorphic change, and mostly far short of this. 



IV. WOODWARDIAN LABORATORY NoTES.^ 



Part III. — The Bagshot Beds of the Bagshot District. 

 By W. H. Herries, B.A. Cantab. 



THE district to which the following notes refer is that which lies 

 between Bagshot, Woking, Aldershot, Farnborough and Ascot. 

 It consists mainly of heath-land, and seems but little known to 

 geologists ; in fact, the only authority for the beds included in this 

 area is Professor Prestwich, who, in his paper on the Bagshot Beds 

 [Q.J.G.S. vol. iii. (1847), p. 278], has supplied all the information 

 about the district that is at present known. He divided the beds 

 1 Contiuued from Decade II. Vol. VII. 1880, p. 458. 



