Coal. 
193 
feet below sea-level under Sydney come to the surface 
at Bulli, Newcastle, and Lithgow (Fig. 48 will make 
this clear). Their outcrop makes a great semi-circle, 
with Sydney for a centre. 
From the standpoint of the general reader, the 
most impressive fact connected with our coal measures 
Fic;. 50 . — Protoretopora aiupla 1 Lonsdale. A Fossil Polyzoan from 
Permo-Carboniferous Hocks at Raymond Terrace, and Harper’s 
Hill. 1, Cast of cellular surface, nat. size, la, Magnified 
representation of a cast of the cellular surface. 
is their occurrence at so great a depth below the surface. 
Obviously, every coal-seam must have at one time been 
a mass of living vegetation on the surface. Coal is 
essentially nothing more or less than somewhat 
decomposed and very much crushed and compressed 
Strzelecki’s New South Wales ami Van Diemen’s Land. Plate ix., as FenwtelUi. 
X 
