On the Geology of the Island of Montreal. 215 



curved lines, parallel to its upper rim or edge, excepting at the 

 sides, where they diverge, leaving a space occupied by other 

 lines of dottings, parallel to the former, but speedily terminat- 

 ing on the cheeks of the buckler. The lines which are com- 

 plete from side to side, are four in number. The imperfect 

 additional ones vary from two to four ; the smallest and inner 

 consisting of only two or three punctures. A plain edging 

 includes the semicircle of punctures. (Vide PI. XV. fig. 1.) In 

 the beds of these casts, the places of the punctures are shown, 

 by small conical elevations, and those of the ridges of the 

 network by corresponding depressions. 



Orthoeeratites are met with, in all the kinds of limestone : 

 those in the dark granular form, are sometimes almost as large 

 as the celebrated specimens from Lake Huron, and vary from 

 them in no respect. Small cylindrical casts of calcspar, which 

 taper considerably, are common. Having no peculiarities of 

 structure, they are only thought to belong to this family, on 

 account of their being provided with a siphuncle. 



Conularia quadrisulcata are rare, but have been found. 

 They are described by Sowerby. Casts of trochi, turbones, 

 terebratulcc, producti, turbinolia, cellular madrepores, co- 

 rallines, retipores, fustra, are every where in great plenty. 

 There is a beautiful variety of the tubipore, which occupies a 

 knot in the calcareous strata ; not confusedly, as is common, 

 but in concentric circles, and placed perpendicularly in the 

 rock, at some distance from each other. I do not know if the 

 tubes communicate with each other. Lingula. exceeding an 

 inch in length are frequent at the west end of the Lachine 

 canal, having the brown matter of the shell in fine preserva- 

 tion. The encrinital family is in astonishing numbers and 

 variety ; but they have not as yet been carefully studied. In 

 May 1823, 1 met with a beautiful specimen of the column and 

 stomach of the E. moniliformis ; a variety of the stag's horn 

 encrinite is not uncommon. The remains, which I last summer 

 consideredj (with others,) to be a fragment of the stomach of 



