ENVIRONS OF NICE. 443 



or a pale bluish-grey ; both are mixtures of argillaceous and 

 calcareous matter. The former often occurs without the lat- 

 ter, and when together, it always assumes the uppermost situa- 

 tion. Of the blue clay bricks and tiles are manufactured, and 

 I think it might be applied with success to the fabrication of 

 pottery, as it forms a tough adhesive paste when kneaded with 

 water, and is of a delicate pale-red colour when burnt. 



It is in this particular kind of clay that a considerable varie- 

 ty of shells are found, of kinds also which are all to be met 

 with alive in the Mediterranean. A few of them I found in the 

 most perfect state of preservation ; but in general they were so 

 much decomposed, that it was very difficult to withdraw them 

 from the clay. In almost every valley, these deposites are to 

 be found, and although some kinds of shells may prevail more 

 in one than in another, still they are throughout generally the 

 same varieties, and possess a character peculiar to the clay in 

 which they occur. 



In one situation, where the deposite was simply of sand, and 

 not many inches thick, I found a great quantity of bivalve 

 shells, principally pectens, and other small kinds of the ostrea, 

 but not one univalve. In the particular situation I now allude 

 to, I have no doubt that the shells were in a very recent state, 

 if not alive, when they were left by the sea. It is true, that 

 for one unbroken which I found, I threw aside the fragments 

 of hundreds; yet it seems to be impossible, that shells so deli- 

 cate and so minute, could submit to the action of transporta- 

 tion. Besides, the quantity that are here found together, be- 

 speaks the probability of an original bed. Oyster-shells I have 

 observed in the same bank, in so perfect a state, that I could 

 not have believed them to be any thing but recent, had I not 

 disengaged them with my own hands. Some of them were 

 attached to pieces of gravel, not agglutinated by means of cal- 



& K 2 careous 



