Fig. 7. Chasmolithic algal growth in
granite, surface of a vertical crack in
the rock, Sonoran Desert, Mexico Route
8, 70 k m from Puerto Penasco. Scale in
mm. Original.
Fig. 6. Examples of hypolithic algal
growth, all viewed from the lower surface which was in contact with the soil.
a: Quartz from desert pavement, Mojave
Desert, California Route 58.
Algal
growth is restricted to a translucentwhite zone of the opaque-violet stone; b:
Calcite from desert pavement, Nevada,
US Road 95 at junction to Cold Creek;
c: Limestone from desert pavement,
Negev Desert, near Sde Boqer; d: Flint
from desert pavement, Negev Desert, km
56 on the road Beer-Sheva - Sodom; c:
Quartz pebble, Egypt, E of Heliopolis;
/ : Fossil Tridacna shell fragment, Negev
Desert, near Eilat. Scale in cm. Original.
Fig. 8. Endolithic algal growth in
crystalline limestone. Cross section-like
portion of the vertically fractured rock.
Negev Desert, Makhtesh Gadol, X38.
Original.
Fig. 9.
Endolithic algal growth in
amorphous fossiliferous limestone. Cross
section-like portion of the vertically
fractured rock. Negev Desert, km 76 on
the road Sodom-Eilat (cf. Fig. 13). X38.
Original.