1894.] Geology and Paleontology. 951 
“The problem of where to draw the line in this series of limestones, 
on a geologic map, between the Cambrian and the Ordovician, is one 
that will seriously embarrass the geologist, but I anticipate that either 
lithologie or paleontologie characters will be discovered by which the 
two groups can be differentiated. If not, the limestones must be col- 
ored as one lithologic unit or formation and the approximate line of 
demarkation between the Cambrian and Ordovician indicated in the 
columnar section accompanying the legend of the map.’ 
Geology of Bathurst, New South Wales.—Bathurst is the 
centre of a region of considerable geological importance, and geologists 
are indebted to Mr. W. J. C. Ross for a detailed account of the forma- 
tions of that district. The Bathurst Plains is a tract of undulating 
country surrounded by hills. The Plains form an extensive granite 
area estimated at 450 square miles, while the hills are of metamorphic 
rock, probably all Silurian. To the east of Bathurst they are backed 
by an escarpment of Devonian quartzites and sandstones. <A few of 
the western hills are capped by basalt resting on Gravels, indicating 
‘volcanic eruptions in the district. 
In discussing the age of the Granite, the author states that it is newer 
than the Silurian, but its relative age with respect to the Devonian is 
uncertain. He is inclined to think that there have been two intrusions, 
one subsequent to the Silurian and prior to the Devonian ; and tke 
second disturbed the Devonian strata, converting the sandstones into 
quartzites, A series of veins which traverses the central mass of gran- 
ite is probably connected with the second intrusion. (Quart. Journ, 
Geol. Soc., Vol. L, 1894.) - 
Fossil Tipulidae.—In a paper on Tertiary Tipulidae recently 
published by Samuel H. Scudder, the author describes twenty-nine new 
species of 10 genera of Limnobinæ and twenty-two new species of 5 
genera of Tipulidæ from Florissant, Colorado, only. From facts now 
known Mr. Scudder concludes that three principal insect localities in 
western Colorado and Wyoming are deposits in a single body of water, 
the ancient Gosiute Lake. To the fauna of these deposits he applies 
the term Gosiute Fauna, in distinction from the Florissant or Lacustrine 
Fauna in central Colorado. No single species of the Lacustrine fauna 
occurs in the Gosiute, and among the few genera found in two of the 
localities of the Gosiute fauna, the species of each locality are distinct 
from those of the other, 
