4 BULLETIN 65, UNITED STATES NATIONAL MUSEUM. 



The destruction by fire of the museum buildmg at the University of 

 Missouri some years ago resulted in the loss of all of Spencer's orig- 

 inal types. No additional specimens of some of his species have come 

 to hand in later collections, so that such species must rest on their 

 descriptions and figures alone. However, it must be stated that all 

 specimens quoted in the descrij^tions, other than Spencer's figured 

 types, are still extant. 



Professor Spencer has published a detailed section of the rocks at 

 Hamilton, which is repeated here for ready reference of the grapto- 

 lites to their horizon. 



Geologic section at Hamilton, Ontario.'^ 



This section was measured along tlie brow of the escarproeut at the city of 

 Plaiuilton, between the ravine at the liead of .Tames street and the '" Jolly Cut " 

 road, about half a mile to the eastward. 



Niagara Formation. 



Thickness 



in feet. 



Bed No. 12. Thin gray dolomites with an abundance of cherty 



nodules. This bed is known as the " Chert bed," and forms the 



-brow of the escarpment at Hamilton and eastward, being 3SS feet 



above lake at head of James street. At head of Queen street this 



series is 10 feet thick 12.0 



Bed Nos. 11 and 10. Argillaceous dolomites, with shaly partings — 

 upper portion known as the " Blue Building beds." Beds 0..5- 



1 foot thick 15.5 



Bed No. 9. Dark hard dolomitic shales and dolomites weathering to 



gray — and lower beds most shaly 10.5 



Bed No. 8. Thick bed gray crystalline dolomite (nearly pure) 4.5 



Bed No. 7. Argillo-arenaceous dolomite in beds from 1-1.5 feet thick. S. S 



51. 3 



Clintox Formation. 



Bed No. Oft. Earthly dolomite, with shaly partings 8.0 



Bed No. 6rt. Clinton shales, all dolomitic. with thin beds of harder 

 rock, some of which are arenaceous, and others to a thickness of 

 about 7 feet are areno-ferruginous. The upper 9 feet may be 



considered as passage beds 76.9 



Bed No. 5. Passage beds of argillaceous dolomites. (Top project- 

 ing portion is glaciated, and is 254 feet alwve lake) 8. 8 



93.7 



Medina Formation. 



Bed Nos. 4 and 3. Coarse, gray sandstone — " Gray Band." This 

 bed varies in thickness 6.5 



Bed Nos. 2 and 1. Medina variegated red and green shales. Thick- 

 ness from calculation of Dundas artesian well 538.5 



545. 



Total thickness 690. 



a J. W. Spencer, Canadian Naturalist, X, 1883, p. 136. 



