The skulls in this case correspond to an average sized "Normal" skull and then the "Giant" skull scales out to be a natural size for a giant 8-9 feet tall, well within the size range recorded in historical records.
MiscalculationIn a study published in 1988, John S. Michael reported that Samuel G. Morton’s original 19th-century data were more accurate than Gould had described; that "contrary to Gould's interpretation . . . Morton's research was conducted with integrity". Nonetheless, Michael's analysis suggested that there were discrepancies in Morton’s craniometric calculations. In another study, published in 2011, Jason E. Lewis and colleagues re-measured the cranial volumes of the skulls in Morton's collection, and re-examined the respective statistical analyses by Morton and by Gould, concluding that, contrary to Gould's analysis, Morton did not falsify craniometric research results to support his racial and social prejudices, and that the "Caucasians" possessed the greatest average cranial volume in the sample. To the extent that Morton's craniometric measurements were erroneous, the error was away from his personal biases. Ultimately, Lewis and colleagues disagreed with most of Gould's criticisms of Morton, finding that Gould's work was "poorly supported", and that, in their opinion, the confirmation of the results of Morton's original work "weakens the argument of Gould, and others, that biased results are endemic in science." Despite this criticism, the authors acknowledged that they admired Gould's staunch opposition to racism.
I am not interested in pursuing that debate at this time, but I would like to point out that the lower two of Morthon's illustrated Alaskan skulls display the distinctive traits of two of Newmann's categories for Native American skulls: the one on the left tends to the older and more "Australoid" kind of skull and the one on the right has more "Inner Asian" or "Alpinoid (Turkmenian)" features also seen later in skulls common in the Western parts of North America, from the Aleutians to the Great Plains, and appearing in the record in parts of Alaska at about 3000 BC, reaching as far as Northern Mexico at the equivalent of the age of Classic Greece in the Old World. This is comparable to the statements made in Men Out of Asia, which was actually in turn reporting on the findings of Dixon and others. This is probably all in the category Stephen Jay Gould disliked so much and was arging against, but against that I would say that arguing against the evidence of an Ethnic diversity is also necessarily being racist. (The Inner Asian type was followed up by a more typically Mongol type into the Western states and influencing also the Inuit or "Eskimoes", with distinctive features such as smaller eye sockets and a shallower base of the skull)