HOLLAND, MI (WHTC News) - Gas prices continued their downward spiral along the Lakeshore, as this morning’s weekly survey of retailers in and around Holland showed a per-gallon average of $3.47, 20 cents below the mean of last Friday. However, the eventual boomerang effect may be evident with reports of rates of around $3.60 and above in the outlying areas of Vriesland, Allendale and Saugatuck. Triple-A’s daily national mark stood at $3.60.