EE es SR aE mee Wee A ORY SEM 
5. Monks Island or Colombian Guano; by Dr. A. 8. Precor, (Proe. 
Amer. Phil. Soc., Philad. vi, 18¥).—In the spring of 1855, there was 
a great effort made to involve in mystery the whole history of the article, 
its locality being carefully kept secret. Gradually, however, it became 
known that it was found on Los Monges, a collection of keys at the en- 
trance of the Gulf of Maracaibo. It has also been found on El Ronca- 
dor, off the Musquito coast, on Aves and various other keys of the Carib- 
an Sea. On Los Monges, it forms, as the captains who procured it - 
say, a thin polished crust over the entire surface. Below this crust lies 
the common Mexican guano. In some instances, however, this same 
- smooth incrustation covers thinly the jutting points of primitive and met- 
amorphic rocks. I have before me a splinter of rock of this kind, crested 
with an inch-thick deposit of this guano; and I have seen many in which 
the white crust formed a thin lamina over the surface. any such were 
attracted attention, and many analyses were made o 
Sulphuric acid, - “ . 2 0% 
Chlorine, - - A z ? reais 
os ; ‘ : ere 
— a : j jon LORD - trace, 
uorine, é - oe : F z os 4 
Sand (consisting chiefly of primitive rocks in powder,) coe 
Water (hygrometric, é ne BI A bil ¢ 2 
Organic matter, salts of ammonia (containing 0°22 o ant 
monia) and combined water, - | Mi 
in which are the alkalies (not estimated,) - ie Satie 
100-00 
| Kin wet Thus, in 
The proportions of the phosphates vary in different samples. Thus, 
one Specie recently demon, there was a very small proportion of 
Magnesia and 4-23 per cent of phosphate of iron. 
