HOVEY : ARTESIAN V\' ELL AT KEY WEST. 71 



Above 700 feet the material was so comminuted, probably by the drill, 

 that it seems impracticable to differentiate the Miocene and Pliocene 

 beds. The surface oolite ceases between the depths of 25 and 50 feet, 

 which may indicate that the top of the Tertiary is there. Furthermore, 

 it seems that the marked change in the appearance of the beds betweeu 

 375 and 400 feet from the surface must be of some significance. 



The following notes on the samples of the borings from the Artesian 

 well at Key West will give an idea of the condition and composition of 

 the material examined. 



Surface. — Color yellowish white. The surface rock consists of an oolitic 

 limestone which pulverizes with comparative ease between the fingers. The 

 nuclei of the ovules are for the most part rounded or subangular calcareous 

 grains, but one ovule was observed which was built up around a grain of 

 quartz. The matrix consists of minutely comminuted stuff. No fragments of 

 either shells or coral were observed. The rock left the merest trace of quartz 

 sand behind on treatment with HC1, like that which is fully described under 

 the material from 250 feet and deeper. 



25 feet. — Color yellowish white. Oolite; hke the above, apparently, though 

 the sample consisted of nothing but the ovules. Not even a trace of the quartz 

 sand noted. After a time a flocculent brownish white precipitate settled out of 

 the HC1 solution. A flocculent precipitate like this, but varying in color to a 

 greenish black, w r as obtained with almost all the samples. See Analysis, p. 85. 



50 feet. — Color white with yellowish and brownish portions. A compact, 

 somewhat sparry limestone filled wuth fragments of foraminifera, corals, re- 

 mains of echini, lamellibranchs, gastropods, etc. Crystals of calcite are present, 

 as is true of many of the other samples. The rock contains vast numbers of 

 foraminifera and other calcareous micro-organisms. No quartz sand, appar- 

 ently. The rock is oolitic, but is not friable like the two preceding. It is 

 mainly a shell limestone with much oolite and foraminii'eral rock. 



75 feet. — Color gray-white. A compact limestone containing pieces of 

 coral and porous lumps. Under the microscope the rock is seen to contain 

 fragments of shells and coral in a fine granular base in which are some forami- 

 nifera. There is a very small amount of limpid quartz sand present and a 

 heavy gray-white flocculent precipitate settles out from the HC1 solution 

 after a little time. 



100 feet. — Color white. Compact limestone containing abundant remains 

 of corals and shells, pectinoids, and other lamellibranchs. Some of the shell 

 fragments are in a matrix of oolite. Very, very small amount of quartz sand. 

 Much of the flocculent precipitate in HC1. The lamellibranchs predominate 

 among the determinable remains. 



