BRODIE 
— GEOLOGY OV 
GLOrCESTERSHIRE. 
289 
but useful method we hope ta teach some really practical ideas of 
geological plienomena. 
Impracticable ia the present state of knowledge, it would take 
years to construct such an entire map of the first dry lands, 
and we have, therefore, selected a portion containing the typical 
district, and which is certainly correct in its great features, 
though still wanting iu some details ; and in the primitive lands 
there pourtrayed, the long ridge extending along the western 
margin of the whole American continent, from the northernmost point 
ofEussian America through the Isthmus of Panama to Cape Horn, 
the lunulate mass on the north side of the lakes encircling Hudson Bay, 
with the outlying islands and patches, appear at a glance as the frame- 
work upon which the existing territory has been elaborated and 
expanded in the great geological ages which have passed away, and in 
these remnants the primitive lands are probably very nearly represented, 
for, as the rock-masses were elevated, it would naturally follow that the 
more newly-raised and outer or marginal portions would be degraded 
by the action of the waves, and form the source of the materials of the 
subsequent deposits during successive geological periods. 
(To be coiiiinued.) 
CONTRIBUTIONS TO THE GEOLOGY OF GLOUCESTERSHIRE. 
THE LIAS. 
By the Rev. P. B. Bkodie, M.A., F.G.S., kc, kc. 
[Conliuiied fromp:if/e 233.) 
Tiie beds immediately below the Marlstonc, which consist of laminated 
shales and clays often micaceous and sandy, were well exposed at the 
latter place during the formation of the reservoirs, and at Robinswood 
Hill, near Gloucester, and at Chipping Campden, on the north-eastern 
extremity of the county, a locality which deserves a special visit. In 
this part of the series, at the base of the Marlstone, a good deal of 
ironstone prevails, which, it is said, was in ancient times worked near 
Gloucester ; it is of some thickness and of excellent quality at Campden. 
These beds are no where destitute of fossils, among which, at the last- 
named place, we may especially notice the fine Ojilnodeniia Guvei/i 
(one of the biittle-stars,--' some species of which are so frequent in our 
* Some of the recent OpliiuviJas have a .singula!- habit of shaliing otf their 
tender arms when touched, as if in defiance of their captor, and o\Ying to tliis, it 
is almost impossible to obtain specimens in perfection. — P. R. B. 
