Marine Deposits near Williainstown. 37 



•referred to as living species, nearly all of which can be found 

 living in the waters of the bay, although several of the forms are 

 not now common on the neighbouring coast (e.g. Murex umbili- 

 catus, Solen vaginoides, etc.). The beds are also traversed in 

 places by seams of hard travertine in which almost all trace of 

 the shells, from which they have been derived, has disappeared. 

 This formation is no doubt due to the action of meteoric waters. 



The very large number of shells present, and their perfect 

 state of preservation, point to the beds not being of the nature of 

 ■drifted sands or dunes. Even tlie most fragile of the Gasteropoda 

 such as Haminea brevis, Eunaticina umbilicata, Amphibola 

 fragilis, Diala monile, Turbonilla mariae, and Turbonilla spina 

 are rarely found in a broken state, while a large percentage of 

 the Lamellibranchs are found as double valves, and appear to be 

 in situ, showing no signs of being much weathered or of having 

 ^travelled very far. Other similar beds along the coast present 

 the same features in this respect, and to the west of the mouth 

 ■of the Werribee, shell beds more extensive than those at Altona 

 •occur. They are there intersected by numerous sewerage 

 channels, and consequently exhibit many tine sections, but we 

 have not had an opportunity of investigating them throughly. 

 The regular bedding of the shells, in every case, is worthy of 

 notice — those of an estuarine type, such as Ophicardelus, 

 Amphibola, etc., being frequently found in layers by themselves, 

 interstratified with others of a more purely marine type — 

 apparently pointing to alterations from time to time in the 

 conditions under which the deposits were laid down. All the 

 beds show a slight dip following the contour of tlie hill which 

 they form. On sinking through the beds on the floor of the 

 deepest part of the cutting to a distance of about 3 feet, a 

 decomposed wackenitic clay was met with, which gave place to 

 the ordinary basalt of the district at a greater depth. 



The top of the beds was ascertained to be 1\ feet above 

 ■ordinary high water, and as the perfect condition of the shells 

 renders it improbable that they are wind blown, further evidence 

 would appear to be here present of at least 10 feet rise in the 

 Jevel of the land bordering this part of the bay during recent 

 geological time. 



