IN THE ISLE 0E PORTLAND AND AROUND WEYMOUTH. 



37 



Cyrene media. 

 Physa Bristovii. 

 Hjdrobia. 



Planorbis. 



Cypris striato-punctata. 



legumen or fasciculata. 



This mass of debris is angular or subangular, and is little or not 

 at all worn— weathered only. It is not stratified, but roughly 

 spread out with thin intercalated irregular seams of the same loam 

 as d'. The loam itself shows traces of rough stratification, and con- 

 tains thin lenticular seams of the angular debris, indicating the 

 one and the other to be phases of the same phenomenon. 



Near where the loam and rubble thin out is another feature which 

 deserves notice. The old beach is here a loose shingle, and has 

 been worked and removed over a considerable extent. This cleared 

 area presents, however, a series of low ridges or walls, running nearly 

 north and south, which have been left by the workmen. On exami- 

 nation these are found to consist of the loam and rubble beds, d' and 



Fig. 5. — Section showing the longitudinal breaks caused in the old 

 beach by fissures filled by land-materials from above, but open 

 ■ Shingle-pit, between section 4 and the landmark. 



d 

 d' 



e 

 Base of pit 



12 



is 



o «H 

 tc ^ 



_ I © 



u 



1. Purbeck beds. 2. Portland rock. d. Soil and dark loam, with angular 

 fragments. d\ Loam, laminated, e. Raised beach. /. Open fissures. 



d, which have replaced the shingle. The cause of this is not difficult 

 to find. On prolonging these loam-ridges to the edge of the cliff 

 further southward, I invariably found them to correspond with one 

 of the many lines of fissuref by which the island is traversed from 



be referred to Nos. 57, 70, 77, and 82 of his section of Ridgeway (see Damon's 

 Geol. of Weymouth, p. 107). 



f These fissures follow the lines of joint, which run within a few degrees on either 

 side of N. and S., and, with the same variation, E. and W. A N.-and-S. fissure 

 will sometimes pass into oneE. and W., and afterwards resume its first direction. 

 They are not caused by an outward, or seaward, slip over the Kimmeridge Clay ; 

 for the beds dip slightly inwards, or inland, forming a shallow synclinal running 

 vN". and S. along the centre of the island. In the above section (fig. 5) the lower 

 part of the debris above / is represented too fine : it consists of large and small 

 angular blocks of Purbeck and Portland beds. 



