32 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
B. Hypersthene gabbro, Wetheredville, Baltimore County. Kedabekose. Rich in 
hypersthene and diallage, with plagioclase, magnetite, and apatite. P. R. C. 1747. 
C. Gabbro diorite, Ilchester, Howard County. Hessose. A coarse anorthite-horn- 
blende rock, probably an altered gabbro. P. R. C. 1748. 
D. Biotite diorite, Triadelphia, Montgomery County. Bandose. P. R. C. 1749. 
E. Biotite diorite, Georgetown, D.C. Bandose. P. R. C. 1750. 
To these may be added an analysis made for Williams by L. G. Eakins, record No. 
1350, as follows: : 
F. Hornblende diorite, Rock Creek tunnel shaft, Washington, D.C. III. 4. 4. 4, 5. 
Relations to E not stated. 
A B Cc D. E F. 
55.97 | 56. 41 56. 18 
15.60] 15.19 | 14.76 
1,21 1.60 2.12 
6. 28 6. 24 6.98 
6. 83 7.18 8.11 
7.31 6.77 7.97 
2.93) 2.21 1.62 
1. Ft 1. a - 80 
185| 200 } 1.37 
1.11 #09, [ersecmes 
-16 05 .08 
seveesee ald |eewminests 
-04 405) |e sceamex 
08 ad. 17 
trace | trace |!......- 
100.10 | 100.06 | 100.16 
The following rocks, from Cecil County, are described by A. G. Leonard in Am. 
Geologist, vol. 28, p. 135. 
G. Quartz-mica-hornblende diorite, near the foundry on Stone Run. Bandose. 
Contains hornblende, biotite, quartz, plagioclase, and a little orthoclase, with acces- 
sory zircon, apatite, titanite, and magnetite, and secondary chlorite and epidote. 
H. Like G, near Porter’s Bridge on Octoraro Creek. Bandose. 
I. Hornblende diorite poor in quartz, three-fourths mile northwest of Rising Sun. 
Corsose. 4 
J. Norite, 1 mile west of Oak Grove schoolhouse. Kedabekose. Contains hypers- 
thene, bytownite, a little diallage, apatite, magnetite, and secondary hornblende. 
Analyses by Hillebrand, record No. 1755. 
G. H. I J 
SIO ge wpasnaeneeeroticicnmies Ss SWFA RSET EES EN Mee aeae see REREEINE 58.57 | 55.16 | 44.04 48.02 
ANG 8 dec reese cerns qeeetem science ke wae eae usar = sebekematinee 16.10 | 17.51 | 20.01 20.01 
Fe2O gy sisisicc s qciccknine bade nasiandeandeaiagcaie stineeieteissee sae 2.89 2.62 4, 22 1.13 
BOQ aictdetscinsiisiecesiccsi isis cin saat ieheeatemnninisie sie sigeieioretstetbiet |e Boe 6.12 5.83 8.61 7.29 
IME O oss wenaeiteton seks a clas oaeeiareteeaaatyenss on wacenectalaageg weTee 2. 33 4.35 5.01 10. 05 
CA Owics2enseucinassmees ee see reeeareeaseer seers eeeecseeeerse 7.39 8.50 | 11.68 11.42 
NaaQ sane sez citeeaiemtineed nr dveeeeeawaiine ss eekeermgneeriias seen 2.11 1.83 1.24 OL 
BO es et ci ahaha ear Swe PR Ne ie de oo tenia -| 1.01 1.08 15 05 
FAG OAC NOD oe aia apcyans nin ncrass sianenis wiresnternne owe a sesaagatanaining sistas asece : 21 .18 el -10 
Es © ADO VE) L0G es occas OY seine cermeniincieg haseediamepasemeds HORNE=ES -| 1.27 2.01 1.90 57 
iO2.... 1.41 64 2,24 23 
P2035 37 21 52 trace 
ZrO 09 +02 -10 none 
Vi03 02 -04 05 02 
CreO3 none | trace | none 03 
NiO, CoO none -O1 01 01 
NO ven ead sececneea eee: sake dereceseeeeeseseemeeeameeesecesee 18 215 28 18 
BrO’. yeni eaedieesemcniies Vorkeaeeeacene ss emeeed ereeagts seed trace | trace | none none 
Ba’ ca chin. Sccigeaaserey ses eee ee oh Peed atte kee trace | trace | none none 
MeO a Scoscciissaicigrs Malclemaseeinie Sad LenS ile GRO RET eee eaSE ee trace | trace | trace trace 
OB ic ch bs Neal tre fetesnnn spel b\digasgeaderasgbln ge eveisscdbad eadigns eatebles nine trace - 03 25 li 
CO si isis Sats ose oohile ie dn Ganka tated me Direct ia Soyer Ora eae eae none | none] none 25 
100.07 | 100.17 | 100, 42 99.98 
