NATURAL HISTORY SOCIETY OF GLASGOW. 333 



The following remarks illustrate the conditions in which the 

 several species are found in the strata in which they occur : — 



G. marginalis. This slender species is very abundant in the shale 

 at Hairmyres. It, however, is seldom found in greater lengths than 

 f of an inch. Some of these fragments show its mode of 

 branching at intervals. In the shale at Gillfoot and Boghead 

 this species is more sparingly found. 



G. stellijwra. Moderately common in the shale at Hairmyres, in 

 fragments rarely exceeding | of an inch in length. The fragments 

 which show the star-pores in the best state of preservation are 

 those obtained by washing the weathered shale. In the other 

 localities noted in the text this form is rare. Recently, we have 

 obtained a portion of a fine frond of this species from the polyzoa 

 shale at Dikehead pit. High Blantyre, measuring 2J inches in 

 length, and 2 inches in breadth. This specimen shows the 

 branching habit of the Polyzoon very distinctly. 



G. elegans. Moderately common in the shale at Hairmyres, in 

 fragments rarely exceeding \\ inches in length. This species is 

 also found at the following localities, in the shales of which, 

 however, it is less common than at Hairmyres : — viz., Craigenglen 

 and Corrieburn, Campsie ; Boghead, near Hamilton ; Capelrig, 

 East Kilbride ; Newfield quarry and Dikehead pit. High Blantyre. 

 At Dikehead we have found fronds of this species measuring 3J 

 inches in length and 2 inches in breadth. 



G. o.sijera. We have only, as yet, obtained this species from the 

 shale at Hairmyres, where it is rare. It is found in the form of 

 small branching fronds, rarely exceeding J inch in length. In the 

 weathered shale it is found in smaller fragments. 



G. flexicarinata. This species is somewhat rare. In the shale 

 at Hairmyres it is found in fragments of fronds rarely exceeding 

 J inch in length. At Dikehead pit, High Blantyre, it is found in 

 frao-ments of branchinsr fronds that measure about 2 inches in 

 length. It also occurs in the limestone shales at Boghead and 

 Capelrig, in small fragments. 



G. retroflexa. This form is abundant in the shale at Hairmyres, 

 in fragments of fronds about 2 inches in length, also in smaller 

 fragments in the shale. It is also a common species in the shale 

 of the lower limestone series of the Beith and Dairy districts, in 

 Ayrshire, where we have found it in fragments of fronds 2 J inches 

 in length. It is also found at Boghead, near Hamilton. 



