466 THE CANADIAN NATURALIST. [V^ol. 



Vll. 



Although the entire thickness upward from the Pentamerus 

 band is only 63 feet near the head of Wellington Street, it 

 increases to the west, and near Dunuas it attains to 127 feet. 

 Eastward of Hamilton it diminishes considerably. The beds 

 are usually irregular in thickness, the thicker bands often in n 

 very short distance splitting up into thin layers, and rendering- 

 it impossible to identify the exactly corresponding beds, even 

 over a limited area. Yet, by means of the Pentamerus bed it is 

 not usually difficult to separate the base of the Niagara from the 

 underlying Clinton. The next most noticeable bed is the third 

 member, which is a hard dolomite, and although continuous, 

 varying in thickness from three to six feet. This is extensively 

 quarried, and forms an excellent building material. Some of 

 the argillaceous limestones would doubtless make good hydraulic 

 cement. 



Fossils are not so abundant as they are farther east, where the 

 upper beds, which are wanting at Hamilton, are developed. 

 The two most important groups of fossils which have been 

 recently discovered at Hamilton are sponges and reticulated 

 graptolites; the former being found in the cherty parts of the 

 top member of the series, while the latter are found in this as 

 well as in the members below. The cherty beds affording the 

 sponges thin out both to the east and west of Hamilton. Two 

 years ago also. Col. Grant, — who discovered the graptolites three 

 or four years since, and the sponges in 1874 — obtained the 

 bodies of certain crinoids, the presence of which had previously 

 been recognized only by the stems or columns. 



Besides several plants, some of which are not determinable, 

 the principal fossils that can be obtained at or near Hamilton 



are : 



ReceptacuUtes, Aulocopina Granti, and other sponges not yet 

 determined; Favosites Gotldandica, Stenopora Jibrosa, Zaprhen- 

 tig Stokesi, Diphyphyllam ; Dictyonema gracilis^ D. recti/ormis, 

 and a number of other graptolites not yet described ; Stephano- 

 crinus angulatus, Caryocrinus ornatus, Eucalyptocrinus decorus ; 

 three species of starfishes ; Fenestella elegans, F. prism, Clado- 

 pora cervicornis, Fhcenopora consteUata ; Leptcena transversalis, 

 L. subplena, Strophomena rhomboidcdis, S. profunda, aS\ Philo- 

 mela, S. Leda, Lingula ohlonga, L. ohlata, and several other 

 species; Liscina formosa, I), tenuilamellata, Orthis elegantula, 

 O.porcata, O. ftaheUiduin, Rhynchonella negJecta, Fentamerus oh- 



