800 General Notes. [September, 
Ba Farani slaves compelled the traveler to retreat. 
ticulars of the massacre of the Italian expedition under Count 
Porro are contained in a recent number of the Bolletino della 
Societa Geographica de Italia. It appears that the Emir 0 
Harrar has suddenly been fired with fanaticism, which prompts 
him to expel all Christian traders. On April 25 he attacked 
the British post of Gialdessa, took captive the Arab and Somali 
garrison and the escort of the Italians, and killed all the Italians 
of the expedition. 
GEOLOGY AND PALAONTOLOGY. 
WALCOTT ON THE CAMBRIAN OF Norra AmERIcA.—Mr. Wal- 
cott has contributed to the August issue of the American 7 
nal of Science an able essay upon the Cambrian system. fte 
regards the Potsdam of New York and the Mississippi valley, 
with Dicellocephalus, as Upper Cambrian; while the Cambrian of 
Newfoundland and Braintree, Mass., with Paradoxides, he places 
dle Cambrian age. Between the Silurian and the granite Poe 
_ Eureka district (Nev.), the lower 1500 feet of quartzites corre- 
= Sponds to the upper half of the 3000 feet of quartz! ti 
~ Satch, and the Olenellus shales occur at the summit of the qua 
dte. ` But between these shales and the Silurian lie over ote i i 
t Aimestone with a fauna uniting the Middle Cambrian W! 
