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POPULAR SCIENCE REVIEW. 
related to a plagiostome fisli, which he and M. de Koninck have styled P. 
imiffuis. 
Keiv Zealand Saurian Remains. — In a paper read before the Philosophical 
Institute of Canterbury, New Zealand (June 3), Dr. Haast read a paper, in 
which he gave a sketch of a saurian from the Waipara which differs from 
any saurian remains hitherto discovered. The specimen belonged to the 
sub-order Amphicoelia. 
Death of two eminent Geologists . — It is with much pain that we have to 
record the loss during the quarter of two very eminent geologists, Professor 
Beete Jukes and Mr. W. J. Salter. The latter, we regret to say, committed 
suicide while in a state of unsound mind. It is said that Hull will 
succeed Professor Jukes in the Irish appointment. Mr. Salter had for some 
time retired from the active pursuit of geology. 
How to Determine an Unseen Fault . — In an excellent practical paper in 
the Geological Magazine (August), and which we commend to the young 
geologist, Mr. II. B. Medlicott makes the following useful remarks : In 
determining the existence, position, and amount of an unseen fault in strati- 
fied rocks, great attention has to be directed to the dips and strike of the 
strata. I would thus partially account for an error that seems to have 
gained credit with many field geologists, that the existence of a fault can 
be detected from a one-sided examination of the dips — from the arrangement 
of the strata on one side of the supposed fault. The question is a vital one, 
for it obviously comes most frequently into operation in important cases of 
apparently great master-faults,” where later sedimentary rocks are in 
juxtaposition with crystalline, or widely distinct masses. The origin of 
such a notion is, perhaps, traceable to the fixed idea ” of the fundamental 
principle of geology — the s?//?e;*-position of the younger deposits. However 
this may be, it would seem to be a rule with many observers at once to set 
down as a fault any abrupt, steeply inclined, junction of rocks of different 
ages, and showing signs of disturbance. A reference to any actual area of 
the earth’s surface would, in the first place, remind one that in any basin of 
deposition new strata must often abut against steep surfaces of the old sup- 
porting rock. And upon the second point (that of disturbance), a brief 
consideration would satisfy one that a subsequent lateral compression, modi- 
fied by slightly varying conditions of resistance, might produce any imagin- 
able complexity of dips in the younger strata near such contact. 
The Fresh-water Deposits of the River Lea . — Mr. II. Woodward read a 
paper descriptive of these before the British Association. Certain excava- 
tions made by the East London Water Works Company had revealed the 
presence of shell marl on the Walthamstow marshes. The marl was accom- 
panied by vegetable remains, and bog-iron ore. All the shells are recent, 
and the most notable fact connected with the bed was the presence of bronze 
spear-heads, arrow-heads, knives, &c. These were accompanied by bones 
of man, wolf, fox, beaver, wild boar, red-deer, roebuck, fallow-deer, rein- 
deer, &c., as well as of the sea-eagle, and fishes. As late as the year 1700 
the entire tract was forest-land. In 1154 the same country is described as 
abounding in wolves, wild boar, wild bulls, &c. Mr. Woodward thought 
that the maintenance of a royal forest had been the means of preserving this 
bed. In the deep cutting of the bed, remains of the Mammoth were met 
