313 



CHAP. XVI. 



On the Deposits colled tertian/ and fresh-water 

 Formations. 



GEOLOGY yet wants a fit name for those deposits of 

 strata which are later than the Chalk. If the older 

 rocks, up to this point, conld be rightly distinguished 

 into primary and secondary only, the word tertiary 

 would be sufficiently appropriate ; but under the 

 better classification which I shall hereafter propose, 

 some other distinction will be necessary. The term 

 fresh-water formations is in every way objectionable ; 

 since it confounds the deposits of antient marine aes- 

 tuaries or basins, with those of fresh-water lakes. 



On this subject, our information is still imperfect, 

 rapidly as it has increased of late ; partly because of 

 limited observations, and partly because of hypotheti- 

 cal and false views respecting some of the principal 

 deposits ; misleading other observers to substitute, 

 imagination for facts. But I hope to show that many 

 distinct things have been confounded under one term ; 

 and with the consequence, as I trust, of hereafter 

 procuring better observations from the geologists who 

 may undertake this subject. When this shall happen, 

 there will be little difficulty in filling up the details of 

 what I must here give in the most general manner. 



Whatever confusion may have been made on this 

 subject, this general character belongs to all ; to those 

 which properly demand the present place, to the strata 

 mentioned in the last chapter, and to the alluvial de- 

 posits of the testuaries of the present ocean ; namely, 

 that they arc found lying on the chalk, or on whatever 

 stratum of the great marine series happens to be upper- 



