This exculpates Darwin for the time from his return from the Beagle voyage till 1844. Hence, the period for which there is no evidence that Matthew's ideas are present in Darwin's work, the records of his development of ideas, and expression of those concepts in his writing can be shown to extend from the time he was leaving for the Beagle voyage, up until the coalescence of his ideas into his cohesive system of evolution by natural selection in 1858. Niles Eldredge, points out the very valid point that seeing Matthew's descriptions at any point during that extended period, would likely have resulted in an integral, preformed model being described by Darwin from the outset, whereas what we actually have in his notes is realisation of the full picture from development of incremental sketches,