Accordingly, thick adobe brick walls and low-pitched or flat roofs usually characterize Spanish Colonial architecture; whereas, French colonial houses are more often timber framed with high-pitched roofs.     Early Colonial settlers (1600-1780) initially designed and constructed their new homes in a style that closely resembled their previous houses in Europe. However, weather conditions in America were harsh as compared to the milder European climate. Conventional building materials were scarce in the colonies making deviations from the former European designs inevitable. As an example, steep English roofs were replaced by lower pitched structures when it was determined that thatched roofing material performed poorly on homes in the new world. Split shingles, or "shakes," that do not require a steep pitch to shed water, replaced thatched roofs.     Colonial Revival houses of the early twentieth century were not necessarily copies of the original colonial homes. Characteristically, these homes were eclectic combinations of various colonial details.