ou Dr. Troost on Amber, §- 
the iiitiscn: is to be observed, and this seems owing, at the 
= examined, to a small undulation.t 
Below this, is a stratum of sand intermixed with, pyrites, 
in which are often found large nests of this mineral, 15 to 
20 feet in square surface, and from one foot to one foot and 
an half in thickness. The quantity of pyrites this bed pro- 
duces is astonishing ; having cleared off its superincumbent 
strata of sand and lignite, (a surface of ein of 1700 square 
feet,) it gave mne, excluding the pyrites, which were broken 
up into small pieces, upwards af t weaty-five tons. This 
stratum is here and there entirely wanting, its place being 
then occupied by shaly clay. 
There eg a bed of earthy lignite. from 5 to 12 feet 
in thickness, embracing a great abundance of pyritous wood, 
intermixed with large fragments, thirty and more feet long, 
of bituminous wood. This bed is intersected by streaks 
and nests of a a grey clay EES fine. gre in Ai 
sy qu nd nstance, 
s found, two substances which 
1 ndance in ihe: wanitve rocks, fifteen or twenty 
niles Mitesce f Bs a here, principally near Baltimore 
“dn this stratum of lignite, was found a substance which i 
at first sight mistook for a fruit, endeavouring to find its 
analogy among the palm fruits. Phe -< rror soon, however, 
became manifest from the observation, tat what had. been 
aiken for the stem of the fruit, was not implanted i in it, but 
raversed its centre, and sometimes perforated its sides— 
po: circum ances bearing no analogy to the stem of fruits. 
The substance was there subjected to a more attentive 
investigation, the result of which led to the belief, that it 
vas an animal product of a very curious nature, and that it 
could be cabins else buta kind of comb or nidus made by 
some insects around the twigs and extremities of the succu- 
lent branches of a tree. 
es <t * these nests is from one to > three inches” in 
ngth, their diameters varying in pro rtion—for instance, 
if the nest have aa: = senate 
co commonly one ‘inch ; if one i 
ter will ae. hal 
oe See Note second at the aket ths Memohe': 
