PRESIDENT'S ADDRESS. Ixxiii. 



The volume includes the description of a craniometer for 

 measuring the profile of skulls, and living heads, invented by 

 General Pitt Rivers. 



Mr. Aubrey Strahan's recently-published Memoir on the 

 Geology of Purbeck and Weymouth is a most valuable contribu- 

 tion to the Geological History of this County. Another memoir 

 by Mr. Clement Reid on the Grits of the south-western part of 

 Hampshire and the south-east of Dorset will shortly follow. 

 The maps are already published, the letter press is in the hands 

 of the printer. Mr. Strahan considers that "the district includes 

 a length of coast which is hardly surpassed in interest in any 

 other part of England. This interest may be said to culminate 

 in the various coves, &c., about Lulworth, which furnish an 

 example of coast-erosion which cannot be easily matched 

 elsewhere. The coast here has been so thoroughly intersected 

 by the fractures of the rocks and the inroads of the sea, that its 

 stratigraphical structure is elaborately exposed. This will not be 

 so always, for as time goes on the erosion which has favoured 

 this present state of things will have passed away, and the 

 evidences of disturbances which have affected this part of the 

 coast will have disappeared, and nothing be left but the chalk- 

 cliffs to be eroded by the sea." The Wealden, which is fluviatile, 

 has scarcely any calcareous deposit ; it is 2,oooft. thick in Pur- 

 beck, and composed of sands, grits, and red or mottled-clays, 

 thinning out very rapidly westward. The deposition of the 

 Weald was by river action, by which clay, sand, and gravel 

 were irregularly and locally distributed in a subsiding area. 

 There are some shales at the top of the Weald at Punfield con- 

 taining an estuarian fauna. Mr. Strahan shows that the Portland 

 and Purbeck beds have a distinct division. This is not the 

 case with the overlying Wealden, either palaeontologically or 

 stratigraphically. During the deposition of the Purbeck beds, 

 which were laid down under lacustrine conditions, the area was 

 liable to incursions of the sea, causing a temporary semi-marine 

 fauna. Mr. Strahan attributes the " broken bands" to the falling in 

 of an underlying mass of decaying vegetation after solidification. 



