4i 



ance with the number of species found, as nearly as may be. The 

 fossils listed from Charleston come mainly from the artesian-well 

 borings. The last column of this series contains space for the listing 

 of fossils from localities where only a few species have been found, 

 and is headed simply "Other Places." After this are columns to 

 sho\v whether or not the different species lived in other geologic ages 

 preceding the Pleistocene and what ages, also whether or not they 

 are still living. In this last particular a blank opposite a name does 

 not necessarily mean that the species is extinct ; it means simply that, 

 so far as known, the species is not still living. In these columns and 

 in the preceding the cross mark (X) indicates that the species is 

 found in that locality or in that age. In the first column for geologic 

 ages, "Pre-Miocene," the following initial letters are used : E for 

 Eocene; O for Oligocene; C for Cretaceous. Then comes a column 

 to show the relative abundance or scarcity of each species as a Pleis- 

 tocene fossil, so far as this has been learned. In this column the 

 following initial letters are employed : VR for very rare ; R for 

 rare ; U for uncommon ; NU for not uncommon ; C for common ; 

 FA for fairly abundant ; A for abundant ; VA for very abundant. 

 These terms are intended to show a gradual rise in point of numbers 

 from very rare, where only one or two or three individuals of the 

 species have been found in a considerable amount of material gath- 

 ered from any one locality, on up to very abundant, where almost a 

 sixth or fifth, sometimes more, of the material may be of a single 

 species. 



Then are given, in appropriate columns, items concerning the en- 

 vironmental conditions of such Pleistocene species as are still living. 

 First, a column giving the depth range; in this, following Dall in 

 Bulletin No. 37 of the United States National Museum, when no 

 figures are given, it is usually to be understood that the depth is 

 shallow. The figures are given in fathoms, and written with the less 

 depth first ; then a dash (-), and the greater depth ; for example, 3-24, 

 means ranging in depth from 3 fathoms to 24 fathoms. These depth 

 ranges cannot be relied upon without reserve for any one particular 

 beach or limited locality, for they apply to each species throughout 

 its entire geographical range. As is well known, a species living in 

 Massachusetts Bay, say, at a depth of 6-8 fathoms would, on migrat- 

 ing southward, seek ever-increasing depths in order to find waters as 

 cold as it had been accustomed to. In the second column is given 

 the kind of shore or bottom which the species prefers, whether 

 muddy, sandy, gravelly, shelly, rocky or what not. Where a species 



