22 
80’e in the shade, but the nights seemed always cool on deck due to the 
prevailing easterly trade winds* Though the recorded extremes of temper- 
ature for this coast are said to range from 39° to 107°, the average 
maximum is around 80 , the average minimum around 60 . 
A BIT OF HISTORY 
Ascension Bay, our chief collecting ground, was discovered by the 
Juan de Grijalva Expedition- -4 ships, 200 men— on Ascension Thursday, 
1518. This expedition was also the first to see Tulum— as we first saw 
it— from the sea (Fig. ) . Grijalva was on his way south along the 
east coast of Yucatan following his discover of Cosumel, May 3, 1518. 
On May 7 he sailed over to the coast of Yucatan where he passed, as his 
chronicler recorded, "Three large towns separated from each other by about 
two miles. There were many houses of stone, very tall towers, and buildings 
covered with strew... 
"We followed the shore day and night, and the next day toward sunset 
we perceived a city or town so large, that Seville would not have seemed 
more considerable, nor better; one saw there a very large tower; on the 
shore was a great throng of Indians, who bore two standards which they 
raised and lowered to signal us to approach them; the commander did not 
wish it. The same day we can® to a beach near which was the highest tower 
we had seen and one discerned a very considerable town..,. We discovered 
a bay so large that a fleet might enter. It was lined with wooden buildings 
set up by fishermen." 
