463 [Nov. (), 



the tomb called '' tomba dolla vigna grando," tlie sorios; of beds was 

 rather diffei'eiit. 



In a ravine, one ndk^ north-west ot" the town, the bine flay is well 

 exposed, and is ot" eonsiderable thiekness. In it nnnierons shells are 

 found — Cerithium, Scrpida, DentaUiim (2 sp.), ]'em(S, Cardinm, 

 Area, Pi'ctcn, JS'atica, Plcurotoma, CanccUaria, JS\issa, and 

 others. The same elay beds are well exposed on the road to 

 Cetona ; and, again in the neighbourhood of Sarteano, eqnally 

 rieh in marine testacea. Between Sarteano and Chianciano, 

 Carditim is found in the sandstone tnll'. Chianeiano is eelebrated, 

 in the annals of Italian Geology, for the great abnndanee and 

 variety of its tertiary marine shells, whieh oeeur in one or two 

 loealities near the town. 



From Chianeiano the same tertiary formation extends to Monte 

 Pnleiano, otlering sections of gravels and sands, containing beds 

 of oysters. Monte Puleiano itself stands on a lofty insnlated hill 

 of sandstone and gravel. In the sand are many large Ostrea?, and 

 a few Ceriihia oecnr in the nodular caleareons concretions. The 

 formation is traversed by a few almost horizontal beds of very 

 hard sandstone. To the north of Monte Puleiano is the commence- 

 ment of a bleak and arid blue marl district, resembling that 

 so remarkably developed in the neighbourhood of Pienza and 

 8. Quirieo, and with wliieh tlie district of Monte Puleiano and 

 Chinsi was, in all probability, formerly connected. 



2. TepxTIAky Freshwater Formation. 



I now proceed to describe those localities in which tertiary 

 freshwater formations came inuler my observation. 



On the range of Inlls \\hich I have been jnst describing, between 

 Cetona and Sarteano, the road crosses a spnr of limestone rocks, 

 winch, from its compact character, coUnu;, and honeycombed ap- 

 pearance, I at hrst attribnted to the Scaglia formation of the se- 

 condary or cretaceous period. Bnt, on reaching the snnnnit of an 

 elevated table land, I found in it nnmerons tertiary freshwater 

 shells, as Planorbis and LimiKca. It rests against the secondary 

 rocks, and appears to be overlaid by the bine marls containing 

 marine shells. 



Another locality, where the same rock ocenrs, is in the valley 

 of the Bultino, two or three miles soxith-east of Colic, on each side 

 of which are extensive remains of a tertiary lacnstrine formation, 

 throngh which the valley has been cut, and a large plain has 

 been excavated. The lower beds are very arenaceons, and contain 

 caleareons nodules. Near the village of Campigliano is a good 

 section, where some of the upper beds are of a slightly reddish 

 colonr ; bnt, in general, they ImAC the dnll grey appearance of an 

 earthy albcrese, sometimes assnming a concretionary character. 

 The npper beds contain Limmca and Planorbis. This formation 

 extends to Colle, forming a flat, level plain covered with barely a 

 foot of soil. 



