54 
On Dykes of Marble and Quartz, See. 
The author remarks, that the greenstone becomes compact near 
the marble, and assumes a bottle-green colour, traces of limestone 
being common in it; whilst, on the other hand, the marble near 
the greenstone is also changed, so that a passage may be traced 
from one to the other. The author concludes by referring to 
other instances in New South Wales, in which similar phenomena 
have been produced. He mentions one case in lat. 32° 6' south, 
and longitude about 151° east, where, in the neighbourhood of 
the river Page, veins of marble intersect a lava-like trap ; and 
another about 16 miles north of Artliursleigh, where a magni¬ 
ficent tunnel, in white crystalline marble, occurs in the bed of a 
creek surrounded by basaltic rocks. On a branch of the Aber¬ 
crombie river, west of the Dividing Range, and about 40 miles 
south of Bathurst, a similar tunnel of gigantic dimensions, nearly 
800 feet long, and 80 feet high, also passes through a mass of 
white crystalline marble, at the bottom of a ravine in the middle 
of a country of volcanic rocks, and blocks of snow-white quartz. 
The author hopes to be able, at a future time, to describe these 
examples more fully. He alludes to them now to shew, that there 
is reason to believe that these connections of limestone, plutonic 
rocks, and quartz dykes, are not without their application to a 
condition of geological phenomena, to the elucidation of which 
the banks of the Wollondilly have exhibited a clue.— Proceed¬ 
ings of the Geological Society, February 5, 1845. 
Art. V. Algce of Tasmania. By W. H. Harvey, M.D., &c. 
(Continued from page 427, vol. ii.) 
(From the London Journal of Botany , August , 1844.) 
13. Polysiphonia fuscescens, Harv.; frondibus aggregatis, fruti- 
cosis, ramosissimis, articulatis, sulcatis, setaceis; e basi in 
ramis elongatis erecti sdivisis; ramis attenuatis bi-tripinnatis ; 
pinnis pinulisque erecto-patentibus, brevibus, simplicibus v. 
ramulosis, apice fibris hyalinis byssoideis ornatis; articulis 
ramorum diametro 2-4-plo longioribus, ramulorum brevissi- 
mis, 4 striatis; keramidiis,... ? 
