Vol. 69.] SANDSTONE IN A BORING AT SOTJTHALL. 79 



The Tertiary and Secondary Kocks. 



Unfortunately, my attention was not called to the boring until 

 Palaeozoic rocks had been reached, and all the cores of the super- 

 incumbent rocks had been removed. Messrs. Isler, however, have 

 kindly supplied a record of the rocks passed through, and also 

 allowed me to examine small samples of the cores kept by them. 

 In the absence of fossils it is, of course, impossible to draw the 

 exact limits of the various formations passed through. The 

 engineer's record is therefore printed in the sequel, and approxi- 

 mate lines of demarcation are drawn on the evidence that exists. 



Mr. Mears, the engineer, informed me that there was only about 

 6 inches of what might represent the Upper Greensand ; while, from 

 my own observation, I can confirm the entire absence of the Lower 

 Greensand. The Gault, with a layer of phosphatic nodules at its 

 base, rested directly upon the red rocks to be immediately described. 

 As the thickness of Chalk given in the journal is about 100 feet 

 less than at the Richmond boring, it is practically certain that 

 some of the rock marked ' Blue Gault ' is in realitv part of the 

 Chalk. 



The Palaeozoic Rocks. 



These rocks were struck at a depth of 1130 feet, and continued 

 with slight variations down to 1261 feet, the final depth of the 

 boring. There is so close a resemblance between them and the 

 * red rocks ' of the Richmond borehole that Prof. Judd's description 

 of the latter holds for the former. They consist of red and green 

 mottled clays and sandstones, with occasional bands of fine con- 

 glomerate. Mica is a very abundant constituent ; particles of 

 galena occur ; and, upon microscopic examination, minute rhombo- 

 hedra of dolomite proved to be fairly abundant. 



Large quantities of the core were broken up, with the result 

 that fossils were found. These Avere present in a marked type of 

 rock, which occurs in bands varying from about 1 inch to an eighth 

 of an inch in thickness. It consists almost wholly of organic 

 remains, associated with rounded and subangular pebbles of 

 quartz. 



The principal fossils are the remains of fishes, which are 

 fortunately preserved in sufficient perfection to enable Dr. Smith 

 Woodward to make generic determinations of them. They consist 

 of scales and teeth of Holoptycliius, and plates of Bothriolepis. 

 Both these genera are characteristic of the Upper Devonian or Old , 

 Red Sandstone. The appendix by Dr. Smith Woodward (p. 81) 

 gives a description of the more important of these remains. 



Other fossils were found, but for the most part they are of too 

 fragmentary a nature for determination. In the microscopic 

 slides, however, minute bodies which are probably plant-remains 

 are to be seen. These were submitted to Dr. D. H. Scott and 

 Mr. A. J. Maslen. Dr. Scott remarks that they are unlike any 

 Devonian plants with which he is acquainted, and suggests that 



