Geological Society of London. 331 



The inference drawn by the author from the facts recorded in his 

 paper is that these weathered boulders once formed portions of 

 moraines on land from which, for a time, the glaciers had receded, 

 and that, after a succession of seasons sufficient to disintegrate these 

 blocks more or less, an increased snowfall caused such an extension, 

 of the glaciers that the blocks were carried down to the sea and 

 conveyed away in icebergs and by floating ice to the spots where 

 they are now imbedded. As they occur at different horizons, there 

 must have been a repetition of the advance and retreat of the glaciers, 

 such as now occurs in Greenland. 



IIL— June 10, 1885.— Prof. T. G. Bonney, D.Sc, LL.D., F.E.S., 

 President, in the Chair. — The following communications were read : 



1. "Note on the Sternal Apparatus in Iguanodon." By J. W. 

 Hulke, Esq., F.R.S., V.P.G.S. 



The author remarked that although parts of the pectoral arch of 

 Iguanodon had been identified in this country and in Belgium, 

 nothing definite was known of the structure of the sternum itself, 

 and stated that a specimen in the collection of Mr. Beckles, from the 

 Wealden of Hastings, seemed to throw some light upon this point. 

 The specimen in question consists of an azygos bar, from near one 

 end of which two smaller rods diverge laterally, the latter terminat- 

 ing mesially in expanded ends, applied to what the author regarded 

 as the ventral surface of the azygos bar, where they approach each 

 other very closely. These two diverging bones are regarded by the 

 author as the clavicles. All the evidence tends to show that the 

 parts are in their normal relations, in which case the clavicles bear 

 the same relation to the interclavicle as in the pectoral arch of exist- 

 ing Lacertilia. 



The azygos piece is a long flattened bar, widening posteriorly for 

 some distance from the attachment of the clavicles, and then narrow- 

 ing slightly to the posterior extremity. The lateral borders from 

 the clavicles to the widest part are smooth and gently arcuate for the 

 articulation of the epicoracoid ; behind this they are rough and 

 apparently non-articular. The author discussed the nature of the 

 azygos piece, which evidently includes the interclavicle ; but whether 

 it comprises the costal sternum is questionable. There are no indi- 

 cations of the connexion of ribs with its lateral borders, and its 

 figure is quite unlike that of the sternum in existing Lacertilia and 

 Crocodilia. From all its characters the author concluded that the 

 azygos piece represents only the interclavicle, and he suggested that 

 the costal sternum may have been cartilaginous, as in existing 

 Crocodiles. 



2. " The Lower Palgeozoic Eocks of the neighbourhood of Haver- 

 fordwest." By J. E. Marr, Esq., M.A., F.G.S., and T. Eoberts, Esq., 

 B.A., F.G.S. 



The authors in this communication described the sequence of the 

 Lower Palasozoic rocks lying to the north of Haverfordwest and 

 Narberth. Their work is founded on that published by the Geologi- 

 cal Surveyors in their maps, sections and memoirs. 



