WORK OF CHARLES C. MOORE 



361 



Weight in tons per 

 cubic meter. 



Gm 



Most porous pebble bed given 2 . 62 



Average of six, including one with 

 barite and one with limonite infiltra- 

 tions 2.64 



Calcareous Rocks: 

 Average of three chalks (maximum. 



42.8 per cent) 2.69 



Average of five oolites (Jurassic) 2.68 



Carboniferous limestone, dolomitic .... 2 . 82 



Others have less weight and porosity 

 and are probably cherty. 



Average of four Silurian limestones ... 2 . 69 



Argillaceous Rocks: 



The highest porosity of a shale (they 

 are all Paleozoic and many altered 

 or black) is the Pusgill Silurian 



shale 2.72 



Archean schist gives 2 . 74 



Eight slates and schists 2 . 78 



Igneous Rocks: 

 These run from the siliceous — for 

 example : 



Pumice 2 . 25 



Arran pitchstone 2 . 35 



Granite, Cornwall, fresh 2 . 66 



Granite, decomposed 



To the basic — for example : 



Hendre dolerite sill — 



From top 2 . 81 



To center 2 . 91 



Giant's Causeway basalt 2.89 



Amphibolite 3.08 



Serpentine of the Lizard, Cornwall. ... 2 . 59 



Porosity. 

 28 . 52 



22.61 



28.78 



14.58 



9.44 



2.79 



10.00 

 2.32 

 2.69 



63.63 

 0.09 

 2.20 



19.90 



Wet. 



2.28 



2.20 



2.75 



2.60 



Dry. 



2.05 



1.91 



2.5S 



0.12 



2.81 



2.81 



0.64 



2.90 



2.89 



0.79 



2.88 



2.87 



0.90 



.... 



. • . • 



5.90 





• • • • 



Data from Drill Cores 



If we compare these with results obtained by measuring and weighing 

 drill cores, we see that, for the igneous rocks, they are quite comparable. 

 A series of measurements showing the variations in one trap sheet are 

 given by Powers and Lane 11 from 2.5 to 2.6 at the amygdaloid top to 2.9 ^ 



11 Trans. Am. Inst, of Mining Engineers, vol. liv, p. 442. 



