422 FOSSIL AND LIVING SHELLS. April 



subterfuge is, that the various sorts of shells which compose 

 these strata both in the plains and mountains, are the very 

 same with those found in the bay and neighbouring places. 

 Among these shells are three species very remarkable : the 

 first is called ' choros,' already mentioned in our description of 

 Lima ; the second is called ' pies de burros," asses' feet ; and 

 the third ' bulgados,' and these to me seem to preclude all man- 

 ner of doubt that they were originally produced in that sea, 

 from whence they were carried by the waters, and deposited in 

 the places where they are now found. 



" I have examined these parts with the closest attention, and 

 found no manner of vestige of subterraneous fires. No cal- 

 cinations are to be met with on the surface of the earth, nor 

 among the shells ; which, as I have already observed, are not 

 intermixed with earth ; nor are there stones, or any other hete- 

 rogeneous substances found among them. Some of these shells 

 are entire, others broken, as must naturally happen in such a 

 close compression of them, during so long an interval of time. 

 " The pie de burro has its name from the fish enclosed in it, 

 resembling, when taken out, the foot of an ass. This fish is of 

 a dark brown colour, firm and filaceous ; it is an vmivalve, its 

 mouth almost circular, and its diameter about three inches. 

 The bottom of the shell is concave within, and convex with- 

 out. The colour within is perfectly white, the surface very 

 smooth ; the outside scabrous and full of tubercles. Its thick- 

 ness in every part is about four or five lines; and being large, 

 compact and heavy, it is preferred to all others for making lime. 

 " The bulgados, in the Canaries called bulgaos, are snails, 

 not at all differing in their form from the common, but larger 

 than those of the same name found in gardens, being from two 

 inches to two inches and a-half in diameter. The shell is also 

 very thick, rough on the outside, and of a dark brown colour ; 

 and, next to the preceding, makes the best lime. 



" All these species of shell fish are found at the bottom of the 

 sea in four, six, ten, and twelve fathom water. They are caught 

 by drags ; and what is very remarkable is, that no shells, either 

 the same, or that have any resemblance to them, are seen either 



