Jamie's right. But I'll add my two cents:
The "Iroquois" artifacts in musems may belong to one of the following tribes: Mohawk, Oneida, Onondaga, Cayuga, and Seneca, or Tuscarora. Since these tribes share ideas, the bows were of various types and designs. However, there is one design that was very common:
D-bow with no discernable handle
Hickory wood
Rectangular cross section
48" to 58" long
Diamond-shaped nocks
1-1/4" wide at the handle
3/4" wide at the nocks
40lb-80lb draw weight
22" to 28" draw length
Unpainted
No handle wrap
Rawhide string
I've seen Iroquois bow cross sections with decrowned wood, quatersawn type grain, and chased rings. I think the most common were the chased-ring type or they simply used the wood directly under the bark...from a 6"+ diameter logs. Bows from small diameter limbs do not appear to be common.
Hope that helps.